Opel Insignia: Diagnostic Information and Procedures

Opel Insignia B 2018-2024 Service Manual / HVAC & Restraints / HVAC - Automatic / Diagnostic Information and Procedures

HVAC COMPONENT REPLACEMENT REFERENCE

HVAC - Automatic

DTC B0163

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0163

Passenger Compartment Temperature Sensor Circuit

For symptom byte information, refer to Symptom Byte List.

Diagnostic Fault Information

HVAC - Automatic

Circuit/System Description

The ambient light/sunload sensor integrates the sunload sensor and passenger compartment temperature sensor into a single assembly.

The solar sensor is connected to a low reference and a 5 V biased (pull up) signal circuit voltage from the HVAC control module. As the sunload increases, the sensor signal voltage decreases. The signal varies between 0.1 - 4.9 V and is provided to the HVAC control module.

The passenger compartment temperature sensor is a negative temperature coefficient thermistor. A signal and low reference circuit enable the sensor to operate. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0 - 5 V.

Bright or high intensity light causes the vehicle interior temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.

Conditions for Running the DTC

Ignition ON.
The HVAC control module is ON.

Conditions for Setting the DTC

B0163 02

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V for more than 50 ms.

B0163 05

The HVAC control module detects the sensor signal out of range. The signal voltage is greater than 4.9 V for more than 50 ms.

Action Taken When the DTC Sets

The system operates using a default value.

Conditions for Clearing the DTC

The sensor signal is within specified range between 0.1 - 4.9 V.

Reference Information

Schematic Reference

HVAC Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor. It may take up to 10 min for all vehicle systems to power down.

NOTE: The scan tool must be disconnected from the vehicle before performing the next test.

2. Test for less than 10 Ω between the low reference circuit terminal 6 and ground.

If 10 Ω or greater

Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module.
Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If less than 10 Ω

3. Ignition ON.

4. Verify the scan tool Passenger Compartment Air Temperature (Unfiltered) parameter is less than -37ÂºC (-35ÂºF).

If -37ÂºC (-35ÂºF) or greater

Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module.
Test for infinite resistance between the signal circuit terminal 3 and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the K33 HVAC Control Module.

Go to next step: If less than -37ÂºC (-35ÂºF)

5. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the low reference circuit terminal 6.

6. Verify the scan tool Passenger Compartment Air Temperature (Unfiltered) parameter is greater than 113ÂºC (235ÂºF).

If 113ÂºC (235ÂºF) or less

Ignition OFF, remove the jumper wire and disconnect the harness connectors at the K33 HVAC Control Module, ignition ON.
Test for less than 1 V between the signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
Ignition OFF.
Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If greater than 113ÂºC (235ÂºF)

7. Test or replace the B10B Ambient Light/Sunload Sensor.

8. Verify DTC B0163 does not set or the symptom does not occur while operating the vehicle within the Conditions for Running the DTC.

If the DTC or symptom is not corrected.

Replace the K33 HVAC Control Module.

Go to next step: If the DTC or symptom is corrected.

9. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference
Control Module References for HVAC control module replacement, programming and setup

DTC B0163, B0183, or B1405

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0163

Passenger Compartment Temperature Sensor Circuit

DTC B0183

Solar Load Sensor Circuit

DTC B1405

Control Module Voltage Reference Output 2 Circuit

For symptom byte information, refer to Symptom Byte List.

Diagnostic Fault Information

HVAC - Automatic

Circuit/System Description

The ambient light/sunload sensor integrates the sunload and passenger compartment temperature functions within a single assembly.

The solar sensor uses 4 unique circuits as detailed below:

Low reference circuit - This is a common ground for the ambient light/sunload sensor assembly.
Temperature signal circuit - This is the signal circuit for the temperature sensor.
Clock signal circuit - This has 2 functions, via a high side PWM signal, the HVAC control module supplies power to the sensor as well as a clock input for the sensor microprocessor.
Sunload signal circuit - This is used as an output from the solar sensor to the HVAC control module to transmit sun heat (IR) intensity, elevation, and azimuth data.

The sunload sensor is connected to ground and to a clocked power supply through the HVAC control module. This clocked power supply is to power the sensor electronics and to work as a clock generator to the sunload sensor micro controller. The sensor uses a pulse signal for data identification and transferring the sun intensity measurement. At each positive transition from the clocked supply input, the sunload sensor micro controller will shift channels enabling new intensity measurement on the signal output to the HVAC control module. The signal voltage varies between 0 - 5 V.

The passenger compartment temperature sensor is a negative temperature coefficient thermistor. As the air temperature increases, the sensor resistance decreases. The sensor signal varies between 0 - 5 V.

Bright or high intensity light causes the vehicles interior temperature to increase. The automatic HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.

Conditions for Running the DTC

Ignition ON
The HVAC control module is ON.

Conditions for Setting the DTC

B0163 02

The input signal is out of range. The HVAC control module detects voltage less than 0.1 V on the temperature signal circuit.

B0163 05

The input signal is out of range. The HVAC control module detects voltage greater than 4.9 V on the temperature signal circuit.

B0183 02

The input signal is out of range. The HVAC control module detects voltage less than 0.1 V on the solar sensor signal circuit.

B0183 05

The input signal is out of range. The HVAC control module detects voltage greater than 4.9 V on the solar sensor signal circuit.

B1405 02

Clocked supply for multi zone sensor is shorted to ground.

B1405 05

Clocked supply for multi zone sensor is shorted to voltage or open.

Action Taken When the DTC Sets

B0163 02, B0163 05, B0183 02, B0183 05

The system will use the last valid values as a default.

B1405 02, B1405 05

If no value is read at the time of fault, the HVAC control module uses 0 W/m2 as intensity.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

HVAC Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Verification

1. Verify that DTC B1405 02 or B1405 05 is not set.

If DTC B1405 is set

Refer to Voltage Reference Malfunction.

Go to next step: If DTC B1405 is not set

2. Verify the actual inside air temperature, using a thermometer, is less than a 3ÂºC (5ÂºF) difference from the scan tool Inside Passenger Compartment Air Temp. Sensor parameter

If greater than a 3ÂºC (5ÂºF) difference

Refer to Sensor Circuit Malfunction

Go to next step: If less than a 3ÂºC (5ÂºF) difference

3. Verify the scan tool Sunload parameter changes while covering the B10B Ambient Light/Sunload Sensor with a shop towel and changes when shining a bright light on it

If the Sunload parameter does not change

Refer to Sensor Circuit Malfunction

Go to next step: If the Sunload parameter changes

4. All OK.

Circuit/System Testing

Voltage Reference Malfunction

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor. It may take up to 10 min for all vehicle systems to power down.

NOTE: The scan tool must be disconnected from the vehicle before performing the next test.

2. Test for less than 10 Ω between the low reference circuit terminal 6 and ground.

If 10 Ω or greater

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If less than 10 Ω

3. Disconnect the X1 harness connector at the

4. Test for less than 0.3 V between the B10B Ambient Light/Sunload Sensor reference voltage circuit terminal 2 and ground.

If greater than 0.3 V

Repair the short to voltage on the circuit.

Go to next step: If less than 0.3 V

5. Ignition OFF.

6. Test for infinite resistance between the B10B Ambient Light/Sunload Sensor reference voltage circuit terminal 2 and ground.

If less than infinite resistance

Repair the short to ground on the circuit.

Go to next step: If infinite resistance

7. Test for less than 5 Ω between the B10B Ambient Light/Sunload Sensor reference voltage circuit terminal 2 and control circuit terminal 20 X1 at the K33 HVAC Control Module harness connector.

If 5 Ω or greater

Repair the open/high resistance in the circuit.

Go to next step: If less than 5 Ω

8. Replace the B10B Ambient Light/Sunload Sensor and verify the DTC does not reset.

If DTC resets

Replace the K33 HVAC Control Module.

Go to next step: If DTC does not reset

9. All OK.

Sensor Circuit Malfunction

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor. It may take up to 10 min for all vehicle systems to power down.

NOTE: The scan tool must be disconnected from the vehicle before performing the next test.

2. Test for less than 10 Ω between the low reference circuit terminal 6 and ground.

If 10 Ω or greater

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If less than 10 Ω

3. Ignition ON, test for 4.8 - 5.2 V between the signal circuit terminal 3 and ground.

If less than 4.8 V

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
Test for infinite resistance between the signal circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

If greater than 5.2 V

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
Test for less than 1 V between the signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K33 HVAC Control Module.

Go to next step: If between 4.8 - 5.2 V

4. Test for 4.8 - 5.2 V between the signal circuit terminal 4 and ground.

If less than 4.8 V

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
Test for infinite resistance between the signal circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

If greater than for 5.2 V

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
Test for less than 1 V between the signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K33 HVAC Control Module.

Go to next step: If between 4.8 - 5.2 V

5. Test or replace the B10B Ambient Light/Sunload Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference
Control Module References for control module replacement, programming and setup

DTC B0173, B0178, B0509, B0514 or B3933

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0173 02

Upper Left Duct Air Temperature Sensor Circuit Short to Ground

DTC B0173 05

Upper Left Duct Air Temperature Sensor Circuit High Voltage/Open

DTC B0178 02

Lower Left Duct Air Temperature Sensor Circuit Short to Ground

DTC B0178 05

Lower Left Duct Air Temperature Sensor Circuit High Voltage/Open

DTC B0509 02

Upper Right Duct Air Temperature Sensor Circuit Short to Ground

DTC B0509 05

Upper Right Duct Air Temperature Sensor Circuit High Voltage/Open

DTC B0514 02

Lower Right Duct Air Temperature Sensor Circuit Short to Ground

DTC B0514 05

Lower Right Duct Air Temperature Sensor Circuit High Voltage/Open

DTC B3933 02

Air Conditioning Evaporator Temperature Sensor Circuit Short to Ground

DTC B3933 05

Air Conditioning Evaporator Temperature Sensor Circuit High Voltage/Open

Diagnostic Fault Information

HVAC - Automatic

Circuit/System Description

The air temperature sensors are a 2-wire negative temperature coefficient thermistor. The vehicle uses the following air temperature sensors:

Air temperature sensor - left upper
Air temperature sensor - left lower
Air temperature sensor - right upper
Air temperature sensor - right lower
A/C evaporator temperature sensor

This sensor operates using signal and low reference circuits. As the air temperature surrounding the sensor increases, the sensor resistance decreases. The sensor is capable of reading temperatures ranging from -40 to +115ÂºC (-40 to +240ÂºF), with a signal voltage between 0 - 5 V. If the HVAC control module detects a malfunctioning sensor the software uses a default air temperature value. The default action ensures that the HVAC system can adjust the inside air temperature near the desired temperature until the condition is corrected.

Conditions for Running the DTC

Ignition ON.
The HVAC control module is ON.

Conditions for Setting the DTC

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V or greater than 4.9 V for more than 50 ms.

Action Taken When the DTC Sets

The system operates using a default value.

Conditions for Clearing the DTC

The sensor signal is within specified range between 0.1 - 4.9 V.

Reference Information

Schematic Reference

HVAC Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Verification

1. Ignition ON.

2. Verify the appropriate temperature sensor has a parameter displayed in HVAC scan tool information.

If there is no scan tool parameter

Refer to Without Scan Tool Support.

Go to next step: If there is a scan tool parameter

3. Refer to With Scan Tool Support

Circuit/System Testing

With Scan Tool Support

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate temperature sensor. It may take up to 10 min for all vehicle systems to power down.

2. Test for less than 10 Ω between the low reference circuit terminal B and ground.

If 10 Ω or greater

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If less than 10 Ω

3. Ignition ON.

4. Verify the appropriate scan tool temperature sensor parameter is less than -37ÂºC (-35ÂºF).

If greater than -37ÂºC (-35ÂºF).

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
Test for infinite resistance between the signal circuit terminal A and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the K33 HVAC Control Module.

Go to next step: If -37ÂºC (-35ÂºF) or less

5. Install a 3 A fused jumper wire between the signal circuit terminal A and the low reference circuit terminal B.

6. Verify the scan tool temperature sensor parameter is greater than 110ÂºC (230ÂºF).

If less than 110ÂºC (230ÂºF)

Ignition OFF, remove the jumper wire and disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
Test for less than 1 V between the signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
Ignition OFF
Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If 110ÂºC (230ÂºF) or greater

7. Test or replace the temperature sensor.

Without Scan Tool Support

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate temperature sensor. It may take up to 10 min for all vehicle systems to power down.

2. Test for less than 10 Ω between the low reference circuit terminal B and ground.

If 10 Ω or greater

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If less than 10 Ω

3. Test for 4.8 - 5.2 V between the signal circuit terminal A and ground.

If less than 4.8 V

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
Test for infinite resistance between the signal circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

If greater than 5.2 V

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
Test for less than 1 V between the signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K33 HVAC Control Module.

Go to next step: If between 4.8 - 5.2 V

4. Test or replace the temperature sensor.

5. Operate the vehicle within the Conditions for Running the DTC. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

6. Verify the DTC does not set.

If the DTC sets

Replace the K33 HVAC Control Module.

Go to next step: If the DTC does not set

7. All OK

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference
Control Module References for HVAC control module replacement, programming and setup

DTC B018A, B048C, B048F, or B1395

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B018A

Windshield Temperature Sensor Circuit

DTC B048C

Humidity Sensor Humidity Circuit

DTC B048F

Humidity Sensor Temperature Circuit

DTC B1395

Control Module Voltage Reference Output Circuit

For symptom byte information, refer to Symptom Byte List.

Diagnostic Fault Information

HVAC - Automatic

Circuit/System Description

The windshield temperature and inside moisture sensor includes the relative humidity sensor, windshield temperature sensor and humidity sensing element temperature sensor all in one assembly.

This sensor assembly provides information about:

Relative humidity level at the windshield inside the vehicle
Temperature of the windshield inside the vehicle
Temperature of the humidity sensor element

The relative humidity sensor measures the relative humidity of the compartment side of the windshield.

It also detects the temperature of the windshield surface on the compartment side. Both values are used as control inputs for the HVAC control module application to calculate the fog risk on windshield compartment side and ability to reduce fuel consumption by decreasing A/C compressor usage to a minimum without causing any fog. The sensor will also enable partial recirculation mode in order to improve heat-up performance of the passenger compartment under cold ambient temperature conditions without the risk of mist build-up on the windshield. The humidity sensor element temperature sensor supplies the temperature of the humidity sensor element. It is only needed if the thermal contact between the humidity sensing element and the inside windshield surface is not sufficient.

Conditions for Running the DTC

Ignition ON.
The HVAC control module is ON.

Conditions for Setting the DTC

B018A 02, B048C 02, or B048F 02

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V for more than 50 ms.

B018A 05, B048C 05, B048F 05 or B1395 07

The HVAC control module detects the sensor signal out of range. The signal voltage is greater than 4.9 V for more than 50 ms.

B1395 03

The HVAC control module detects the 5 V reference voltage out of range. The 5 V reference voltage is less than 4.5 V for more than 50 ms.

B1395 07

The HVAC control module detects the 5 V reference voltage out of range. The 5 V reference voltage is greater than 5.5 V for more than 50 ms.

Action Taken When the DTC Sets

The system will use the last valid values as default.
If no value is read at the time of fault, the HVAC control module uses 60% for humidity.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

HVAC Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B160 Windshield Temperature and Inside Moisture Sensor. It may take up to 10 min for all vehicle systems to power down.

NOTE: The scan tool must be disconnected from the vehicle before performing the next test.

2. Test for less than 10 Ω between the low reference circuit terminal 3 and ground.

If 10 Ω or greater

Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module.
Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If less than 10 Ω

3. Ignition ON.

4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 1 and ground.

If less than 4.8 V

Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module.
Test for infinite resistance between the 5 V reference circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Test for less than 2 Ω in the 5 V reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

If greater than 5.2 V

Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module, ignition ON.
Test for less than 1 V between the 5 V reference circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K33 HVAC Control Module.

Go to next step: If between 4.8 - 5.2 V

5. Verify the scan tool parameters listed below are less than -37ÂºC (-35ÂºF).

Windshield Temperature
Passenger Compartment Humidity Sensor Temperature
If -37ÂºC (-35ÂºF) or greater

Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module.
Test for infinite resistance between the signal circuit terminals listed below and ground:
- Windshield temperature sensor signal terminal 4
- Passenger compartment humidity sensor temperature signal terminal 5
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the K33 HVAC Control Module.

Go to next step: If less than -37ÂºC (-35ÂºF)

6. Test for 4.8 - 5.2 V between the signal circuit terminals listed below and ground.

Windshield temperature sensor signal terminal 4
Passenger compartment humidity sensor temperature signal terminal 5
If less than 4.8 V

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
Test for infinite resistance between the signal circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

If greater than for 5.2 V

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
Test for less than 1 V between the signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K33 HVAC Control Module.

Go to next step: If between 4.8 - 5.2 V

7. Install a 3 A fused jumper wire between the low reference circuit terminal 3 and each signal circuit terminal listed below:

Windshield temperature sensor signal terminal 4
Passenger compartment humidity sensor temperature signal terminal 5

8. Verify the appropriate scan tool parameter listed below is greater than 114ÂºC (238ÂºF).

Windshield Temperature
Passenger Compartment Humidity Sensor Temperature
If 114ÂºC (238ÂºF) or less

Ignition OFF, remove the jumper wire and disconnect the harness connectors at the K33 HVAC Control Module, ignition ON.
Test for less than 1 V between the signal circuit terminals listed below and ground:
- Windshield temperature sensor signal terminal 4
- Passenger compartment humidity sensor temperature signal terminal 5
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If greater than 114ÂºC (238ÂºF)

9. Remove the jumper wire.

10. Verify the scan tool Passenger Compartment Humidity parameter is greater than 95%.

If 95% or less

Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module, ignition ON.
Test for infinite resistance between the signal circuit terminal 2 and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the K33 HVAC Control Module.

Go to next step: If greater than 95%

11. Test for 4.8 - 5.2 V between the signal circuit terminal 2 and ground.

If less than 4.8 V

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
Test for infinite resistance between the signal circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

If greater than for 5.2 V

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
Test for less than 1 V between the signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K33 HVAC Control Module.

Go to next step: If between 4.8 - 5.2 V

12. Install a 3 A fused jumper wire between the passenger compartment humidity signal circuit terminal 2 and the low reference circuit terminal 3.

13. Verify the scan tool Passenger Compartment Humidity Sensor parameter is less than 5%.

If 5% or greater

Ignition OFF, remove the jumper wire and disconnect the harness connectors at the K33 HVAC Control Module, ignition ON.
Test for less than 1 V between the signal circuit terminal 2 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If less than 5%

14. Test or replace the B160 Windshield Temperature and Inside Moisture Sensor

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference
Control Module References for HVAC control module replacement, programming and setup

DTC B0183

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0183

Solar Load Sensor Circuit

For symptom byte information, refer to Symptom Byte List.

Diagnostic Fault Information

HVAC - Automatic

Circuit/System Description

The ambient light/sunload sensor integrates the sunload sensor and passenger compartment temperature sensor into a single assembly.

Bright or high intensity light causes the vehicle interior temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.

Conditions for Running the DTC

Ignition ON.
The HVAC Control Module is ON.

Conditions for Setting the DTC

B0183 02

The input signal is out of range. The voltage is less than 0.1 V.

B0183 05

The input signal is out of range. The voltage is greater than 4.9 V.

Action Taken When the DTC Sets

The system will use the last valid values as default.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

HVAC Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B10B Ambient Light/Sunload Sensor. It may take up to 10 min for all vehicle systems to power down.

NOTE: The scan tool must be disconnected from the vehicle before performing the next test.

2. Test for less than 10 Ω between the low reference circuit terminal 6 and ground.

If 10 Ω or greater

Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module.
Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If less than 10 Ω

3. Ignition ON.

4. Test for 4.8 - 5.2 V between the signal circuit terminal 4 and ground.

If less than 4.8 V

Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module.
Test for infinite resistance between the signal circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

If greater than 5.2 V

Ignition OFF, disconnect the harness connectors at the K33 HVAC Control Module, ignition ON.
Test for less than 1 V between the signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K33 HVAC Control Module.

Go to next step: If between 4.8 - 5.2 V

5. Test or replace the B10B Ambient Light/Sunload Sensor.

6. Verify DTC B0183 does not set or the symptom does not occur while operating the vehicle within the Conditions for Running the DTC.

If the DTC or symptom is not corrected.

Replace the K33 HVAC Control Module.

Go to next step: If the DTC or symptom is corrected.

7. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference
Control Module References for HVAC control module replacement, programming and setup

DTC B0193

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B0193 01

Front Blower Motor Speed Circuit Short to Battery

DTC B0193 06

Front Blower Motor Speed Circuit Low Voltage/Open

Diagnostic Fault Information

HVAC - Automatic

Circuit/System Description

The blower motor control module is an interface between the HVAC control module and the blower motor. The blower motor control module has 5 circuits: a B+ input, ground, a control circuit from the HVAC control module, a B+ output to the blower motor, and a low side pulse width modulation (PWM) output. The HVAC control module provides a low side (PWM) signal to the blower motor control module in order to request the blower motor speed. The blower motor control module grounds the blower motor using a low side PWM signal in order to vary the blower motor speed.

Conditions for Running the DTC

Ignition ON.
The HVAC control module is ON.

Conditions for Setting the DTC

B0193 01

The voltage at the HVAC control module output to the blower motor control module is always high.

B0193 06

The voltage at the HVAC control module output to the blower motor control module is always low or fluctuating.

Action Taken When the DTC Sets

The blower motor is inoperative.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Diagnostic Aids

Inspect the motor shaft for rust or other foreign material which may prohibit proper motor operation.

If the motor operates properly please reinstall it and check for Preliminary Information or Technical Service Bulletins.

Reference Information

Schematic Reference

HVAC Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the X1 harness connector at the K8 Blower Motor Control Module. It may take up to 10 min for all vehicle systems to power down.

2. Test for less than 10 Ω between the ground circuit terminal 5 and ground.

If 10 Ω or greater

Ignition OFF.
Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground connection.

Go to next step: If less than 10 Ω

3. Verify a test lamp illuminates between the B+ circuit terminal 6 and ground.

If the test lamp does not illuminate and the circuit fuse is good

Ignition OFF, remove the test lamp.
Test for less than 2 Ω in the B+ circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.

If the test lamp does not illuminate and the circuit fuse is open

Ignition OFF, remove the test lamp.
Test for infinite resistance between the B+ circuit terminal 6 and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Disconnect the X2 harness connector at the K8 Blower Motor Control Module and disconnect the harness connector at the M8 Blower Motor.
Test for infinite resistance between the M8 Blower Motor B+ circuit terminal B and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, test or replace the M8 Blower Motor.

Go to next step: If the test lamp illuminates

4. Ignition ON. Test for less than 1 V between the control circuit terminal 3 and ground.

If 1 V or greater

Ignition OFF, disconnect the X2 harness connector at the K33 HVAC Control Module.
Ignition ON.
Test for less than 1 V between the control circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K33 HVAC Control Module

Go to next step: If less than 1 V

5. Ignition OFF. It may take up to 10 min for all vehicle systems to power down.

6. Test for infinite resistance between the control circuit terminal 3 and ground.

If less than infinite resistance

Disconnect the X2 harness connector at the K33 HVAC Control Module.
Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the K33 HVAC Control Module

Go to next step: If infinite resistance

NOTE: Verify the ignition is OFF before connecting the blower motor control module or incorrect test results may occur.

7. Ignition OFF, connect the X1 harness connector at the K8 Blower Motor Control Module. Ignition ON.

8. While backprobing terminal 3 at the K8 Blower Motor Control Module, test for greater than 1 V between the control circuit and ground.

If less than 1 V

Replace the K8 Blower Motor Control Module.

Go to next step: If 1 V or greater

9. Verify the voltage decreases and increases while using the controls to change the blower speed selection.

If the voltage does not decrease and increase as the blower speed selection is changed

Ignition OFF, disconnect the X2 harness connector at the K33 HVAC Control Module.
Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If the voltage decreases and increases as the blower speed selection is changed

10. Ignition OFF, disconnect the harness connector at the M8 Blower Motor, ignition ON and blower ON.

11. Verify a test lamp illuminates between the B+ circuit terminal B and ground.

If the test lamp does not illuminate

Ignition OFF, disconnect the X2 harness connector at the K8 Blower Motor Control Module.
Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω replace the K8 Blower Motor Control Module.

Go to next step: If the test lamp illuminates

12. Connect a test lamp between control circuit terminal A and B+ circuit terminal B.

13. Verify the test lamp becomes progressively brighter as the blower speed is increased and progressively dimmer as the blower speed is decreased.

If the test lamp does not illuminate

Ignition OFF, disconnect the X2 harness connector at the K8 Blower Motor Control Module, ignition ON.
Test for less than 1 V between the control circuit terminal 1 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω replace the K8 Blower Motor Control Module.

If the test lamp illuminates, but does not change in brightness

Ignition OFF, disconnect the X2 harness connector at the K8 Blower Motor Control Module.
Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the K8 Blower Motor Control Module.

Go to next step: If the test lamp changes in brightness as the blower speed is changed

14. Test or replace the M8 Blower Motor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference
Control Module References for control module replacement, programming and setup

DTC B0223, B022A, B0233, B023A, B0408, or B0418

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B0223 01

Recirculate Position Command 1 Circuit Short to Battery

DTC B0223 06

Recirculate Position Command 1 Circuit Low Voltage/Open

DTC B022A 01

Recirculate Position Command 2 Circuit Short to Battery

DTC B022A 06

Recirculate Position Command 2 Circuit Low Voltage/Open

DTC B0233 01

Air Flow Control Circuit Short to Battery

DTC B0233 06

Air Flow Control Circuit Low Voltage/Open

DTC B023A 02

HVAC Actuators Supply Voltage Short to Ground

DTC B0408 01

Main Temperature Control Circuit Short to Battery

DTC B0408 06

Main Temperature Control Circuit Low Voltage/Open

DTC B0418 01

Right Temperature Control Circuit Short to Battery

DTC B0418 06

Right Temperature Control Circuit Low Voltage/Open

Diagnostic Fault Information

HVAC - Automatic

Circuit/System Description

Stepper motors are used for temperature regulation, air distribution control and recirculation door control.

With the switches and dials on the HVAC controls, air temperature door position, mode door position and recirculation door position can be selected. The selected values are passed to the HVAC control module via serial data. The HVAC control module supplies a 12 V control voltage to the stepper motors and energizes the 4 stepper motor coils with a pulsed ground signal. The stepper motors move the appropriate doors into the calculated positions, in order to reach the desired positions.

Conditions for Running the DTC

Ignition ON.
The HVAC control module is ON.

Conditions for Setting the DTC

B023A 02

The stepper motors supply output is shorted to ground.

B0223 01, B022A 01, B0233 01, B023A 01, B0408 01 or B0418 01

At least one control circuits of the appropriate stepper motor is shorted to voltage when motor starts moving. Faults are not detected when motor is already running or target position is already reached.

B0223 06, B022A 06, B0233 06, B0233 06, B0408 06 or B0418 06

At least one control circuits of the appropriate stepper motor is shorted to ground or open when motor starts moving. Faults are not detected when motor is already running or target position is already reached.

Action Taken When the DTC Sets

B023A

The affected output will be switched off for hardware protection.
All stepper motors are deactivated.

B0223, B022A, B0233, B0408 or B0418,

The affected output will be switched off for hardware protection.
The affected stepper motor is deactivated.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

HVAC Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Verification

1. Perform the Actuator Recalibration procedure.

2. Verify the concern or DTC has been corrected.

If the concern or DTC has not been corrected

Verify DTC B023A is not set.
- If DTC B023A is set
Refer to Circuit/System Testing - DTC B023A.
- If DTC B023A is not set
Refer to Circuit/System Testing - DTC B0223, B022A, B0233, B0408 or B0418.

Go to next step: If the concern or DTC has been corrected

3. All OK.

Circuit/System Testing

(DTC B023A)

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the components listed below. It may take up to 2 min for all vehicle systems to power down.

M4 Air Inlet Door Actuator
M37 Mode Door Actuator
M46 Air Recirculation Door Actuator
M6L Air Temperature Door Actuator - Left
M6R Air Temperature Door Actuator - Right

2. Disconnect the X3 and X4 harness connectors at the K33 HVAC Control Module.

3. Test for infinite resistance between the K33 HVAC Control Module 12 V reference circuit terminal 15 X3 and ground.

If less than infinite resistance

Repair the short to ground on the circuit.

Go to next step: If infinite resistance

4. Ignition ON.

5. Test for less than 1 V between the K33 HVAC Control Module 12 V reference circuit terminal 15 X3 and ground.

If 1 V or greater

Repair the short to voltage on the circuit.

Go to next step: If less than 1 V

6. Connect the X3 and X4 harness connectors at the K33 HVAC Control Module, ignition ON.

7. Clear all DTCs.

8. Verify DTC B023A is not set.

If the DTC is set.

Replace the K33 HVAC Control Module.

Go to next step: If the DTC is not set.

9. Verify DTC B023A does not set after connecting each of the components listed below one at a time and operating them through their full range.

M4 Air Inlet Door Actuator
M37 Mode Door Actuator
M46 Air Recirculation Door Actuator
M6L Air Temperature Door Actuator - Left
M6R Air Temperature Door Actuator - Right
If the DTC sets

Replace the component that was connected immediately before the DTC set.

Go to next step: If the DTC does not set

10. All OK.

(DTC B0223, B022A, B0233, B0408 or B0418)

1. Ignition OFF, disconnect the harness connector at the appropriate door actuator, ignition ON.

2. Verify a test lamp flashes when connected between the 12 V reference circuit terminal 2 and ground.

If the test lamp does not flash

Ignition OFF, remove the test lamp and disconnect the harness connector at the K33 HVAC Control Module.
Test for less than 2 Ω in the 12 V control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If the test lamp flashes

3. Connect a test lamp between each control circuit listed below and B+.

Control Circuit - terminal 1
Control Circuit - terminal 3
Control Circuit - terminal 4
Control Circuit - terminal 6

4. Command the appropriate door actuator in both directions.

5. Verify the test lamp turns ON and then OFF during at least one of the directional commands.

If the test lamp is always ON

Ignition OFF, remove the test lamp and disconnect the harness connector at the K33 HVAC Control Module.
Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the K33 HVAC Control Module.

If the test lamp is always OFF

Ignition OFF, remove the test lamp and disconnect the harness connector at the K33 HVAC Control Module, ignition ON.
Test for less than 1 V between the control circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
Ignition OFF
Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance is the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If the test lamp turns ON and then OFF

6. Replace the door actuator.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference
Control Module References for HVAC control module replacement, programming and setup

DTC B269A, B269C, or B269D

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B269A

Heater Coolant Pump Control Circuit

DTC B269C

Heater Coolant Pump Control Circuit Low Voltage

DTC B269D

Heater Coolant Pump Control Circuit High Voltage

Diagnostic Fault Information

HVAC - Automatic

Circuit/System Description

The primary purpose of the heater core coolant pump is to circulate engine coolant through the HVAC heater core when heat is required in the cabin for comfort. This normally happens when the vehicle is in an Auto Stop and the mechanical pump is not spinning. If the HVAC control module has determined heat is needed for the cabin, a request is sent via serial data to the engine control module to turn the pump ON. The engine control module controls the auxiliary coolant pump relay via the heater core coolant pump relay control circuit. The heater core coolant pump relay supplies voltage to the heater core coolant pump.

Conditions for Running the DTC

The 12 V battery voltage is greater than or equal to 9 V.
The auxiliary heater coolant pump enable is commanded.

Conditions for Setting the DTC

The engine control module detects the auxiliary heater coolant pump relay control circuit is open, shorted to voltage or shorted to ground.

Action Taken When the DTC Sets

DTCs B269A, B269C, and B269D are type B DTCs.

Conditions for Clearing the DTC

DTCs B269A, B269C, and B269D are type B DTCs.

Reference Information

Schematic Reference

HVAC Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Testing

1. Ignition OFF, disconnect the X4 harness connector at the X50A Fuse Block - Underhood.

2. Connect a test lamp between the control circuit terminal C4 and B+, ignition ON.

3. Verify the test lamp turns ON and OFF when commanding the G36 Auxiliary Heater Coolant Pump On and Off with a scan tool.

If the test lamp is always OFF

Ignition OFF, remove the test lamp, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
Test for less than 1 V between the control circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
Ignition OFF.
Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.

If the test lamp is always ON

Ignition OFF, remove the test lamp, disconnect the harness connector at the K20 Engine Control Module.
Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the K20 Engine Control Module.

Go to next step: If the test lamp turns ON and OFF

4. Ignition OFF and all vehicle systems OFF, connect the X4 harness connector at the X50A Fuse Block - Underhood. Disconnect the harness connector at the G36 Auxiliary Heater Coolant Pump.

It may take up to 2 min for all vehicle systems to power down.

5. Test for less than 10 Ω between the ground circuit terminal 1 and ground.

If 10 Ω or greater

Ignition OFF.
Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground connection.

Go to next step: If less than 10 Ω

6. Connect a test lamp between the control circuit terminal 2 and ground.

7. Verify the test lamp turns ON and OFF when commanding the G36 Auxiliary Heater Coolant Pump ON and OFF with a scan tool.

If the test lamp is always OFF and the circuit fuse is good

Ignition OFF, remove the test lamp, disconnect the X4 harness connector at the X50A Fuse Block - Underhood.
Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the X50A Fuse Block - Underhood.

If the test lamp is always OFF and the circuit fuse is open

Ignition OFF, remove the test lamp.
Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, test or replace the G36 Auxiliary Heater Coolant Pump.

If the test lamp is always ON

Ignition OFF, disconnect the X4 harness connector at the X50A Fuse Block - Underhood, ignition ON.
Test for less than 1 V between the control circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the X50A Fuse Block - Underhood.

Go to next step: If the test lamp turns ON and OFF

8. Test or replace the G36 Auxiliary Heater Coolant Pump.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference
Control Module References for control module replacement, programming and setup

DTC B3843

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B3843 02

Air Quality Sensor Circuit Short to Ground

DTC B3843 05

Air Quality Sensor Circuit High Voltage/Open

DTC B3843 08

Air Quality Sensor Circuit Performance - Signal Invalid

Diagnostic Fault Information

HVAC - Automatic

Circuit/System Description

The HVAC control module uses an air quality sensor to detect hydrocarbons. This sensor operates using an ignition voltage circuit, a ground circuit and a signal circuit.

This information is sent to the HVAC control module using a pulse width modulated (PWM) signal. It is used only when the automatic HVAC mode is requested by the customer.

When the HVAC module detects the concentration of pollutants exceeds a preset value, recirculation mode is commanded to keep the passenger compartment free of pollutants.

Conditions for Running the DTC

Ignition ON
The HVAC control module is ON.

Conditions for Setting the DTC

B3843 02

No PWM is detected and the signal is low.

B3843 05

No PWM is detected and the signal is high.

B3843 08

The sensor sends a 5% PWM signal indicating an internal sensor short circuit or open circuit.

Action Taken When the DTC Sets

The automatic recirculation mode is disabled.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

HVAC Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B108 Air Quality Sensor. It may take up to 2 min for all vehicle systems to power down.

2. Test for less than 10 Ω between the ground circuit terminal 2 and ground.

If 10 Ω or greater

Ignition OFF.
Test for less than 2 Ω in the ground circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, repair the open/high resistance in the ground connection.

Go to next step: If less than 10 Ω

3. Ignition ON.

4. Verify a test lamp illuminates between the ignition circuit terminal 1 and ground.

If the test lamp does not illuminate and the circuit fuse is good

Ignition OFF, remove the test lamp.
Test for less than 2 Ω in the ignition circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, verify the fuse is OK and there is voltage at the fuse.

If the test lamp does not illuminate and the circuit fuse is open

Ignition OFF, remove the test lamp.
Test for infinite resistance between the ignition circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the B108 Air Quality Sensor.

Go to next step: If the test lamp illuminates

5. Verify a test lamp does not illuminate between the signal circuit terminal 3 and ground.

If the test lamp illuminates

Ignition OFF, remove the test lamp and disconnect the harness connector at the K33 HVAC Control Module. Ignition ON.
Test for less than 1 V between the signal circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K33 HVAC Control Module.

Go to next step: If the test lamp does not illuminate

6. Test for greater than 10 V between the signal circuit and ground.

If less than 10 V

Ignition OFF, disconnect the harness connector at the K33 HVAC Control Module.
Test for infinite resistance between the signal circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If greater than 10 V

7. Replace the B108 Air Quality Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference
Control Module References for control module replacement, programming and setup

DTC B393B

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC B393B

Air Conditioning Compressor Valve Control Circuit

For symptom byte information, refer to Symptom Byte List.

Diagnostic Fault Information

HVAC - Automatic

Circuit/System Description

This A/C system uses a conventional clutch to engage and mechanically turn the compressor and a variable displacement solenoid valve to alter the amount of displacement created by the turning of the compressor. The HVAC control module provides both battery voltage and a pulse width modulated ground to the variable displacement solenoid valve. When the A/C switch is pressed, the HVAC control module grounds the variable displacement solenoid using a low side (PWM) signal in order to command the amount of compressor displacement. The performance of the A/C compressor is based on adjusted interior temperature and engine load.

Conditions for Running the DTC

Ignition ON.
The HVAC control module is ON.

Conditions for Setting the DTC

B393B 04

A PWM greater than 10% is sent but no current is read back.

B393B 0B

Measured current is above threshold of 815 mA.

Action Taken When the DTC Sets

B393B 04

The A/C compressor is disabled.

B393B 0B

The A/C compressor is disabled.
Output will be switched off for hardware protection.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

HVAC Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the Q46 A/C Compressor Solenoid Valve.

Connect a test light between terminals 1 and 2 of the harness connector. Ignition ON.

2. Verify the test light turns on and off when commanding the Q46 A/C Compressor Solenoid Valve ON and OFF with the scan tool.

If the test light does not turn ON and OFF

Ignition OFF, disconnect the X2 harness connector at the K33 HVAC Control Module, ignition ON.
Test for less than 1 V between ground and each control circuit terminal listed below:
- terminal 10
- terminal 11
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
Ignition OFF.
Test for infinite resistance between ground and each control circuit terminal listed below:
- terminal 10
- terminal 11
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Test for less than 2 Ω in each of the control circuits end to end listed below:
- Q46 A/C Compressor Solenoid Valve terminal 1 and K33 HVAC Control Module terminal 10
- Q46 A/C Compressor Solenoid Valve terminal 2 and K33 HVAC Control Module terminal 11
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- Go to next step: If less than 2 Ω, replace the K33 HVAC Control Module.

Go to next step: If the test light turns ON and OFF

3. Test the Q46 A/C Compressor Solenoid Valve or replace the G1 A/C Compressor.

Component Testing

A/C Compressor Solenoid Valve Test

1. Ignition OFF, disconnect the harness connector at the Q46 A/C Compressor Solenoid Valve.

2. Test for 7 - 15 Ω between B+ terminal 2 and control terminal 1.

If less than 7 Ω or greater than 15 Ω

Replace the G1 A/C Compressor.

Go to next step: If between 7 - 15 Ω

3. Test for infinite resistance between each terminal and the Q46 A/C Compressor Solenoid Valve housing/case.

If less than infinite resistance

Replace the G1 A/C Compressor.

Go to next step: If infinite resistance

4. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference
Control Module References for control module replacement, programming and setup

DTC P0532 or P0533

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of the diagnostic category.

DTC Descriptors

DTC P0532

Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit Low Voltage

DTC P0533

Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit High Voltage

Diagnostic Fault Information

HVAC - Automatic

Circuit/System Description

The engine control module (ECM) monitors the high side refrigerant pressure through the A/C refrigerant pressure sensor. The ECM supplies a 5 V reference and a low reference to the sensor.

Changes in the A/C refrigerant pressure cause the sensor signal to the ECM to vary. When the pressure is high, the signal voltage is high. When the pressure is low, the signal voltage is low. The ECM may use this information to turn the cooling fans on as well as to monitor clutch engagement. The HVAC module will receive the A/C refrigerant pressure information from the ECM via serial data.

Conditions for Running the DTC

Engine is running.
Any of the conditions for setting the DTC are met for 15 s.
Battery voltage is between 11 - 18 V.

Conditions for Setting the DTC

P0532

The ECM detects that the A/C pressure is less than 1 psi (0.25 V).

P0533

The ECM detects that the A/C pressure is more than 428 psi (4.92 V).

Action Taken When the DTC Sets

DTCs P0532 and P0533 are Type B DTCs
The A/C compressor is disabled.
The ECM will illuminate the malfunction indicator lamp (MIL).

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Diagnostic Aids

A malfunction within the refrigerant system causing high pressure can cause this DTC to set.

Reference Information

Schematic Reference

HVAC Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.

2. Verify the scan tool engine control module A/C High Side Pressure Sensor parameter is between 6.8 kPa (1 psi) and 2950 kPa (428 psi).

If not between 6.8 kPa (1 psi) and 2950 kPa (428 psi)

Refer to Circuit/System Testing

Go to next step: If between 6.8 kPa (1 psi) and 2950 kPa (428 psi)

3. All OK

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the B1 A/C Refrigerant Pressure Sensor. It may take up to 2 min for all vehicle systems to power down.

2. Test for less than 10 Ω between the low reference circuit terminal 1 and ground.

If 10 Ω or greater

Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
Test for less than 2 Ω in the low reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.

Go to next step: If less than 10 Ω

3. Ignition ON.

4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 2 and ground.

If less than 4.8 V

Ignition OFF, disconnect the harness connector at the K20 Engine Control Module.
Test for infinite resistance between the 5 V reference circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Test for less than 2 Ω in the 5 V reference circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.

If greater than 5.2 V

Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
Test for less than 1 V between the 5 V reference circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K20 Engine Control Module.

Go to next step: If between 4.8 - 5.2 V

5. Verify the scan tool A/C High Side Pressure Sensor parameter is less than.25 V.

If.25 V or greater

Ignition OFF, disconnect the harness connector at the K20 Engine Control Module, ignition ON.
Test for less than 1 V between the signal circuit terminal 3 and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- If less than 1 V, replace the K20 Engine Control Module.

Go to next step: If less than.25 V

6. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 2.

7. Verify the scan tool A/C High Side Pressure Sensor parameter is greater than 4.8 V.

If 4.8 V or less

Ignition OFF, remove the jumper wire, disconnect the harness connector at the K20 Engine Control Module.
Test for infinite resistance between the signal circuit terminal 3 and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Test for less than 2 Ω in the signal circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.

Go to next step: If greater than 4.8 V

8. Test or replace the B1 A/C Refrigerant Pressure Sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference
Control Module References for engine control module replacement, programming and setup

DTC P0645, P0646, or P0647

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P0645

Air Conditioning (A/C) Compressor Clutch Relay Control Circuit

DTC P0646

Air Conditioning (A/C) Compressor Clutch Relay Control Circuit Low Voltage

DTC P0647

Air Conditioning (A/C) Compressor Clutch Relay Control Circuit High Voltage

Diagnostic Fault Information

HVAC - Automatic

Circuit/System Description

When the A/C switch is pressed, the HVAC control module sends an A/C request message to the engine control module (ECM) via serial data. The ECM then grounds the A/C compressor clutch relay coil control circuit, closing the relay contacts. The closed relay contacts provide voltage to the compressor clutch causing it to engage.

Conditions for Running the DTC

Engine is running.
The HVAC control module is ON.
The A/C switch is active.

Conditions for Setting the DTC

P0645 or P0646

The ECM detects a short to ground or an open at the A/C compressor clutch relay control circuit.

P0647

The ECM detects a short to voltage at the A/C compressor clutch relay control circuit.

Action Taken When the DTC Sets

P0645 or P0646

The A/C compressor is inoperative or always active. The A/C compressor solenoid is commanded to 0% displacement. This causes warm air from the ducts, even with unwanted clutch engagement.

P0647

The A/C compressor is inoperative.

Conditions for Clearing the DTC

The condition for setting the DTC is no longer present.

Reference Information

Schematic Reference

HVAC Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the KR29 A/C Compressor Clutch Relay, ignition ON.

2. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.

If the test lamp does not illuminate and the circuit fuse is good

Ignition OFF, remove the test lamp.
Test for less than 2 Ω in the B+ circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, verify the fuse is not open and there is voltage at the fuse.

If the test lamp does not illuminate and the circuit fuse is open

Ignition OFF, remove the test lamp.
Test for infinite resistance between the B+ circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- Go to next step: If infinite resistance
Disconnect the harness connector at the Q2 A/C Compressor Clutch.
Test for infinite resistance between the control circuit terminal 87 and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, test or replace the Q2 A/C Compressor Clutch.

Go to next step: If the test lamp illuminates

3. Ignition ON.

4. Verify a test lamp illuminates between the ignition circuit terminal 86 and ground.

If the test lamp does not illuminate

Refer to Power Mode Mismatch.

Go to next step: If the test lamp illuminates

5. Connect a test lamp between the ignition circuit terminal 86 and the control circuit terminal 85.

6. Verify the test lamp turns ON and OFF when commanding the ECM A/C Compressor Clutch Relay On and Off with a scan tool.

If the test lamp is always OFF

Ignition OFF, remove the test lamp and disconnect the harness connector at the K20 EngineControl Module, ignition ON.
Test for less than 1 V between the control circuit and ground.
- If 1 V or greater, repair the short to voltage on the circuit.
- Go to next step: If less than 1 V
Ignition OFF.
Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, replace the K20 Engine Control Module.

If the test lamp is always ON

Ignition OFF, remove the test lamp and disconnect the harness connector at the K20 EngineControl Module.
Test for infinite resistance between the control circuit and ground.
- If less than infinite resistance, repair the short to ground on the circuit.
- If infinite resistance, replace the K20 Engine Control Module.

Go to next step: If the test lamp turns ON and OFF

7. Verify a test lamp does not illuminate between the control circuit terminal 87 and ground.

If the test lamp illuminates

Repair the short to voltage on the circuit.

Go to next step: If the test lamp does not illuminate

8. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the Q2 A/C Compressor Clutch. It may take up to 2 min for all vehicle systems to power down.

9. Test for less than 10 Ω between the ground circuit terminal 1 and ground.

If 10 Ω or greater

Ignition OFF.
Test for less than 2 Ω in the ground circuit end to end.
1. If 2 Ω or greater, repair the open/high resistance in the circuit.
2. If less than 2 Ω, repair the open/high resistance in the ground connection.

Go to next step: If less than 10 Ω

10. Connect the harness connector at the Q2 A/C Compressor Clutch.

11. Ignition ON, connect a 10 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87.

12. Verify the Q2 A/C Compressor Clutch is engaged.

If the Q2 A/C Compressor Clutch does not engaged.

Ignition OFF, disconnect the harness connector at the Q2 A/C Compressor Clutch.
Test for less than 2 Ω in the control circuit end to end.
- If 2 Ω or greater, repair the open/high resistance in the circuit.
- If less than 2 Ω, test or replace the Q2 A/C Compressor Clutch.

Go to next step: If the Q2 A/C Compressor Clutch is engaged

13. Test or replace the KR29 A/C Compressor Clutch Relay.

Component Testing

1. Ignition OFF, disconnect the KR29 A/C Compressor Clutch Relay.

2. Test for 60 - 180 Ω between terminals 85 and 86.

If not between 60 - 180 Ω

Replace the KR29 A/C Compressor Clutch Relay.

Go to next step: If between 60 - 180 Ω

3. Test for infinite resistance between the terminals listed below:

30 and 86
30 and 87
30 and 85
85 and 87

If less than infinite resistance

Replace the KR29 A/C Compressor Clutch Relay.

Go to next step: If infinite resistance

4. Install a 15 A fused jumper wire between terminal 86 and 12 V. Install a jumper wire between terminal 85 and ground.

5. Test for less than 2 Ω between terminals 30 and 87.

If 2 Ω or greater

Replace the KR29 A/C Compressor Clutch Relay.

Go to next step: If less than 2 Ω

6. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference
Control Module References for engine control module replacement, programming and setup

Symptoms - HVAC Systems - Automatic

NOTE: The following steps must be completed before using the symptom tables:

1. Perform the Diagnostic System Check - Vehicle before using the HVAC System Malfunction procedure in order to verify that all of the following are true:

There are no DTCs set.
The control modules can communicate via the serial data link.

2. Review the system operation in order to familiarize yourself with the system functions. Refer to Automatic HVAC Description and Operation.

Visual/Physical Inspection

NOTE: Shutting one or more outlets may adversely affect the Automatic HVAC system by producing erroneous duct air temperature sensor readings in the duct connecting to the closed outlet. Where possible, always operate the Automatic HVAC system with all outlets open.

Inspect for aftermarket devices which may affect the operation of the HVAC System.
Inspect the easily accessible or visible system components for obvious damage or conditions which may cause the symptom.
Verify the A/C compressor turns freely and is not seized.
Verify that the customer is using the correct key to enable personalization and is not inadvertently activating auxiliary HVAC controls.
The A/C compressor will not operate in cold outside air temperatures.
The following conditions may cause window fogging:
- Wet carpet or mats
- High humidity
- Interior water leak
- Blocked A/C evaporator drain tube
- Maximum passenger capacity
- Blocked body pressure relief valves
Inspect the air distribution system for causes of reduced air flow:
- Obstructed or dirty passenger compartment air filter, if equipped
- Blocked or damaged air inlet or outlet vents

Intermittent

Faulty electrical connections or wiring may be the cause of intermittent conditions. Refer to Testing for Intermittent Conditions and Poor Connections.

Symptom List

Refer to HVAC System Malfunction in order to diagnose the symptom.

HVAC SYSTEM MALFUNCTION

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Aids

Check the following mechanical fault sources:

Air distribution box
Air distribution hoses/air distribution ducts

Reference Information

Schematic Reference

HVAC Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

NOTE: Check for bulletins before proceeding.

1. Ignition ON.

2. Verify every applicable scan tool switch parameter changes when pressing the appropriate switch on the A26 HVAC Controls.

If any parameter does not change

Replace the A26 HVAC Controls.

Go to next step: If all parameters change

3. Verify the blower motor operates properly with the blower motor switch in each speed position.

If the blower motor does not operate properly in each speed position

Refer to DTC B0193.

Go to next step: If the blower motor operates properly in each speed position

4. Verify the HVAC doors listed below move when operating the appropriate control.

Driver Temperature
Passenger Temperature
Mode
Recirculation
If any HVAC door does not move

Refer to DTC B0223, B022A, B0233, B023A, B0408, or B0418.

Go to next step: If all HVAC doors move

5. Install the appropriate ACR Air Conditioning Service Center, ignition ON.

6. Verify the high side pressure on the gauge is within 10% of the scan tool A/C High Side Pressure Sensor parameter.

If the A/C High Side Pressure Sensor parameter is not within 10%

Refer to DTC P0532 or P0533.

Go to next step: If the A/C High Side Pressure Sensor parameter is within 10%

7. Verify the A/C High Side Pressure Sensor parameter is between 269-2929 kPa (39-425 PSI).

If the reading is not between 269-2929 kPa (39-425 PSI)

Refer to Air Conditioning (A/C) System Performance Test

Go to next step: If the reading is between 269-2929 kPa (39-425 PSI)

8. Verify the scan tool parameters listed below are within 10% of ambient temperature.

Lower Left Duct Air Temperature Sensor
Upper Left Duct Air Temperature Sensor
Lower Right Duct Air Temperature Sensor
Upper Right Duct Air Temperature Sensor
A/C Evaporator Temperature Sensor
If not within 10% of ambient temperature

Refer to DTC B0173, B0178, B0509, B0514 or B3933.

Go to next step: If within 10% of ambient temperature

9. Verify the scan tool parameters listed below are within 10% of actual conditions.

Passenger Compartment Humidity
Passenger Compartment Humidity Sensor Temperature
Passenger Compartment Windshield Temperature
If not within 10% of actual conditions

Refer to DTC B018A, B048C, B048F, or B1395.

Go to next step: If within 10% of actual conditions

10. Engine ON, A/C system ON.

11. Verify cool air flows from the ducts with the temperature control in the coldest position.

If the air is not cool

Verify the Q2 A/C Compressor Clutch is engaged.
- If the Q2 A/C Compressor Clutch is not engaged, refer to Air Conditioning Compressor Malfunction.
- If the Q2 A/C Compressor Clutch is engaged, refer to Air Conditioning (A/C) System Performance Test and DTC B393B.

Go to next step: If the air is cool

12. Verify warm air flows from the ducts with the temperature control in the warmest position.

If the air is not warm

Refer to Heating Performance Diagnostic.

Go to next step: If the air is warm

13. Engine OFF, ignition ON.

14. Verify the scan tool Sunload parameter changes while covering the B10B Ambient Light/Sunload Sensor with a shop towel or other suitable item.

If the Sunload parameter does not change

Refer to DTC B0163 or DTC B0183.

Go to next step: If the Sunload parameter changes

15. Verify the actual inside air temperature, using a thermometer, is less than 3ÂºC (5ÂºF) difference from the scan tool Inside Passenger Compartment Air Temp. Sensor parameter.

If greater than a 3ÂºC (5ÂºF) difference
Refer to DTC B0163 or DTC B0183.
Go to next step: If less than a 3ÂºC (5ÂºF) difference

16. Verify the G36 Auxiliary Heater Coolant Pump turns On and Off when commanded with a scan tool.

If the G36 Auxiliary Heater Coolant Pump does not turn On and Off
Refer to DTC B269A, B269C, or B269D.
Go to next step: If the G36 Auxiliary Heater Coolant Pump does turn On and Off

17. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference
Control Module References for control module replacement, programming and setup.

Air Conditioning Compressor Malfunction

Diagnostic Instructions

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The A/C compressor uses a conventional belt driven magnetic clutch to engage and mechanically turn the compressor. When the A/C switch is pressed, the HVAC control module sends an A/C request message to the ECM via serial data. If specific criteria is met, the ECM then grounds the A/C compressor clutch relay control circuit, which will switch the A/C compressor clutch relay. With the relay contacts closed, battery voltage is supplied to the permanently grounded A/C compressor clutch.

The A/C compressor clutch will then be activated.

This A/C system utilizes a variable displacement solenoid valve to alter the amount of displacement created by the turning of the compressor. The HVAC control module provides both battery voltage and a pulse width modulated ground to the variable displacement solenoid valve. When the A/C switch is pressed, the HVAC control module grounds the variable displacement solenoid using a (PWM) signal in order to determine the amount of compressor displacement. The performance of the A/C compressor is regulated based on the adjusted interior temperature.

Diagnostic Aids

The following conditions must be met in order to turn on the A/C compressor:

Battery voltage is between 9 - 18 V.
Engine coolant temperature is less than 124ÂºC (255ÂºF).
Engine speed is greater than 600 RPM.
Engine speed is less than 5 500 RPM.
A/C high side pressure is between 269 - 2 929 kPa (39 - 425 PSI).
Throttle position is less than 100%.
Evaporator temperature is greater than 3ÂºC (38ÂºF).
ECM does not detect excessive torque load.
ECM does not detect insufficient idle quality.
The ambient temperature sensor senses above 1ÂºC (34ÂºF).
Blower motor is ON.

Reference Information

Schematic Reference

HVAC Wiring Schematics

Connector End View Reference

Component Connector End View Index

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

NOTE: Refer to HVAC System Malfunction before performing this procedure.

1. Ignition ON, press and release the A/C Switch.

2. Verify the HVAC control module scan tool A/C Switch parameter changes between Active and Inactive.

If the parameter does not change

Replace the A26 HVAC Controls.

Go to next step: If the parameter changes

3. Set A/C system to coolest setting with blower ON.

4. Press and release the A/C switch several times.

5. Verify the ECM scan tool A/C Request Signal parameter changes between Active and Inactive.

If the parameter does not change

Replace the K33 HVAC Control Module.

Go to next step: If the parameter changes

6. Verify the A/C compressor clutch engages and disengages when commanding the ECM A/C Relay output function On and Off with a scan tool.

If the A/C compressor clutch does not engage or disengage as commanded

Refer to DTC P0645, P0646, or P0647

Go to next step: If the A/C compressor clutch engages and disengages as commanded

7. Engine ON.

8. Verify the HVAC control module scan tool A/C Compressor Refrigerant Solenoid Valve Command parameter changes with varying cooling loads.

If the parameter does not change

Refer to DTC B393B

Go to next step: If the parameter does change

9. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

HVAC Component Replacement Reference
Control Module References for HVAC control module replacement, programming and setup

Afterblow Enabling

Afterblow is a feature that dries the evaporator core by operating the blower motor after the engine is turned off. This aids in reducing microbial growth that can create undesirable odors.

The vehicle does not come equipped with the afterblow feature turned on. If the afterblow feature is required due to an odor concern, it must be enabled by using the scan tool.

Use the following procedure to enable the afterblow feature:

1. Connect the Scan Tool.

2. Ignition ON/ Vehicle in Service Mode 3. Select Module Diagnosis.

4. Select Remote Heater and Air Conditioning Control Module.

5. Select Configuration/Reset Functions.

6. Select HVAC Afterblow Configuration.

When afterblow has been enabled, the following conditions must be met for the HVAC control module to operate afterblow:

The vehicle must be turned OFF.
The outside air temperature must be at least 11ÂºC (52ÂºF) when the compressor was last operating before the engine was turned OFF.
The A/C compressor must have operated for more than 2 minutes before the engine was turned OFF.
The system voltage must be above 12 V.

Once the above conditions have been met, the blower motor will operate at a low blower speed, following the sequence below up to 5 times:

1. The blower motor will be OFF for 7 - 11 minutes.

2. The blower motor will operate for 20 - 60 seconds.

ACTUATOR RECALIBRATION

Preferred Method (with Scan Tool)

NOTE: Do not operate any HVAC controls while the HVAC control module is calibrating as this may interrupt the process. If interrupted, improper HVAC performance will result.

1. Using a scan tool, perform the HVAC Actuators Learn in the HVAC Control Module.

2. Follow the scan tool directions to complete the procedure.

3. Operate the system and verify that no DTCs have set as current DTCs.

4. If DTC B101E 4B is set after attempting the actuator recalibration procedure, perform the following:

Verify which actuator does not have a scan tool learn status parameter status of complete.
Verify the unlearned actuator is physically rotating - A common cause of DTC B101E 4B is an actuator that is electrically OK but fails to physically rotate (e.g. stripped gears).
If the unlearned actuator is not physically rotating, replace the actuator, otherwise replace the HVAC control module.

Alternate Method (without Scan Tool)

NOTE: Do not operate any HVAC controls while the HVAC control module is calibrating as this may interrupt the process. If interrupted, improper HVAC performance will result.

1. Ignition OFF/ Vehicle OFF.

2. Remove the HVAC control module fuse for a minimum of 10 s.

3. Install the HVAC control module fuse.

4. Start the vehicle.

5. Wait 40 s for the HVAC control module to self-calibrate.

SEE MORE:

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