DTC B1405, B1825, B2355, B2365, or B2375 (Driver Seat)
Diagnostic Instructions
DTC Descriptors
DTC B1405
Control Module Voltage Reference Output 2 Circuit
DTC B1825
Seat Recline Position Sensor Circuit
DTC B2355
Seat Front Vertical Position Sensor Circuit
DTC B2365
Seat Rear Vertical Position Sensor Circuit
DTC B2375
Seat Assembly Horizontal Position Sensor Circuit
For symptom byte information refer to Symptom Byte List.
Diagnostic Fault Information
Circuit Description
The seat memory control module monitors the position of the seat motors by using hall effect position sensors which are an internal part of each motor. The module supplies each sensor with a 12 V reference circuit only when any seat motor is active, and a low side signal circuit. During seat motor operation, the hall effect position sensor provides a determined number of pulse signals for every revolution of the motor shaft. The scan tool displays these pulse signals as counts that range from 0 - 65, 535. The module counts the feedback pulses from each sensor to determine seat position and end of travel limits for each of the seat motors. High scan tool count values indicate forward or upward seat positions while low count values indicate rearward or downward seat positions.
Conditions for Running the DTC
Conditions for Setting the DTC
The seat memory control module does not detect position sensor movement or pulse signals while the adjuster motor is active. The following conditions will set this DTC:
B1405 02
The seat memory control module detects a short to ground or an open on the 12 V reference circuit.
B1825 01, B2355 01, B2365 01, or B2375 01
The seat memory control module detects a voltage greater than 5 V on the sensor signal circuit.
B1825 06, B2355 06, B2365 06, or B2375 06
The seat memory control module detects a short to ground or an open on the sensor signal circuit.
Action Taken When the DTC Sets
Conditions for Clearing the DTC
Reference Information
Schematic Reference
Driver Seat Wiring Schematics
Connector End View Reference
Component Connector End View Index
Description and Operation
Memory Seats Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate driver seat motor listed below for which the DTC set:
2. Ignition ON.
3. Test for greater than 10.8 V between the appropriate 12 V reference circuit listed below and ground while pressing any power seat switch.
4. Test for 0.2 - 2 V between the appropriate signal circuit listed below and ground.
5. Test or replace the seat motor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
DTC B1405, B1825, B2355, B2365, or B2375 (Passenger Seat)
Diagnostic Instructions
DTC Descriptors
DTC B1405
Control Module Voltage Reference Output 2 Circuit
DTC B1825
Seat Recline Position Sensor Circuit
DTC B2355
Seat Front Vertical Position Sensor Circuit
DTC B2365
Seat Rear Vertical Position Sensor Circuit
DTC B2375
Seat Assembly Horizontal Position Sensor Circuit
For symptom byte information refer to Symptom Byte List.
Diagnostic Fault Information
Circuit Description
The seat memory control module monitors the position of the seat motors by using hall effect position sensors which are an internal part of each motor. The module supplies each sensor with a 12 V reference circuit only when any seat motor is active, and a low side signal circuit. During seat motor operation, the hall effect position sensor provides a determined number of pulse signals for every revolution of the motor shaft. The scan tool displays these pulse signals as counts that range from 0 - 65, 535. The module counts the feedback pulses from each sensor to determine seat position and end of travel limits for each of the seat motors. High scan tool count values indicate forward or upward seat positions while low count values indicate rearward or downward seat positions.
Conditions for Running the DTC
Conditions for Setting the DTC
The seat memory control module does not detect position sensor movement or pulse signals while the adjuster motor is active. The following conditions will set this DTC:
B1405 02
The seat memory control module detects a short to ground or an open on the 12 V reference circuit.
B1825 01, B2355 01, B2365 01, or B2375 01
The seat memory control module detects a voltage greater than 5 V on the sensor signal circuit.
B1825 06, B2355 06, B2365 06, or B2375 06
The seat memory control module detects a short to ground or an open on the sensor signal circuit.
Action Taken When the DTC Sets
Conditions for Clearing the DTC
Reference Information
Schematic Reference
Passenger Seat Wiring Schematics
Connector End View Reference
Component Connector End View Index
Description and Operation
Memory Seats Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate passenger seat motor listed below for which the DTC set:
2. Ignition ON.
3. Test for greater than 10.8 V between the 12 V reference circuit listed below and ground while pressing any power seat switch.
4. Test for 0.2 - 2 V between the appropriate signal circuit listed below and ground.
5. Test or replace the seat motor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
DTC B1735, B1740, B1745, B1750, B1755, B1760, B1815, or B1820 (Driver Seat)
Diagnostic Instructions
DTC Descriptors
DTC B1735
Seat Front Up Switch Circuit
DTC B1740
Seat Front Down Switch Circuit
DTC B1745
Seat Rear Up Switch Circuit
DTC B1750
Seat Rear Down Switch Circuit
DTC B1755
Seat Assembly Forward Switch Circuit
DTC B1760
Seat Assembly Rearward Switch Circuit
DTC B1815
Seat Recline Forward Switch Circuit
DTC B1820
Seat Recline Rearward Switch Circuit
For symptom byte information refer to Symptom Byte List.
Diagnostic Fault Information
1. Power seat is inoperative
Circuit/System Description
The seat memory control module supplies a reference voltage to each signal circuit of the driver seat adjuster switch. When the power seat switches are pressed, the appropriate signal circuit from the seat memory control module is pulled low through the switch contacts indicating the power seat command.
The seat memory control module then commands the driver seat to move in response to the switch signals.
Conditions for Running the DTC
Conditions for Setting the DTC
Action Taken When the DTC Sets
Conditions for Clearing the DTC
Diagnostic Aids
Reference Information
Schematic Reference
Driver Seat Wiring Schematics
Connector End View Reference
Component Connector End View Index
Description and Operation
Memory Seats Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
1. Ignition ON.
2. Verify the scan tool seat switch parameters listed below change between Inactive and Forward/Rearward or UP/Down when pressing the appropriate seat directional switch.
Refer to Circuit/System Testing.
3. All OK.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the S64D Seat Adjuster Switch - Driver.
2. Clear present DTCs to enable system.
3. Verify that all scan tool driver seat switch parameters listed below are Inactive:
4. Install a 3 A fused jumper wire between the appropriate signal circuit terminal listed below and the ground circuit terminal E.
5. Verify the appropriate scan tool seat switch parameter is Forward/Rearward or UP/Down.
6. Test or replace the S64D Seat Adjuster Switch - Driver.
Component Testing
Seat Adjuster Switch Test
1. Ignition OFF, disconnect the harness connector at the S64D Seat Adjuster Switch - Driver.
2. Test for infinite resistance between the ground terminal E and each signal terminal with the switch in the open position.
Replace the S64D Seat Adjuster Switch - Driver.
3. Test for less than 2 Ω between the ground terminal E and each signal terminal with the appropriate switch in the closed position.
Replace the S64D Seat Adjuster Switch - Driver.
4. All OK.
Repair Instructions
Driver or Passenger Seat Adjuster Switch Replacement
DTC B1735, B1740, B1745, B1750, B1755, B1760, B1815, or B1820 (Passenger Seat)
Diagnostic Instructions
DTC Descriptors
DTC B1735
Seat Front Up Switch Circuit
DTC B1740
Seat Front Down Switch Circuit
DTC B1745
Seat Rear Up Switch Circuit
DTC B1750
Seat Rear Down Switch Circuit
DTC B1755
Seat Assembly Forward Switch Circuit
DTC B1760
Seat Assembly Rearward Switch Circuit
DTC B1815
Seat Recline Forward Switch Circuit
DTC B1820
Seat Recline Rearward Switch Circuit
For symptom byte information refer to Symptom Byte List.
Diagnostic Fault Information
1. Power seat is inoperative
Circuit/System Description
The seat memory control module supplies a reference voltage to each signal circuit of the passenger seat adjuster switch. When the power seat switches are pressed, the appropriate signal circuit from the seat memory control module is pulled low through the switch contacts indicating the power seat command.
The seat memory control module then commands the passenger seat to move in response to the switch signals.
Conditions for Running the DTC
Conditions for Setting the DTC
Action Taken When the DTC Sets
Conditions for Clearing the DTC
Diagnostic Aids
Reference Information
Schematic Reference
Passenger Seat Wiring Schematics
Connector End View Reference
Component Connector End View Index
Description and Operation
Memory Seats Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
1. Ignition ON.
2. Clear present DTCs to enable system.
3. Verify the scan tool seat switch parameters listed below change between Inactive and Forward/Rearward or UP/Down when pressing the appropriate seat directional switch.
Refer to Circuit/System Testing.
4. All OK.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the S64P Seat Adjuster Switch - Passenger.
2. Verify that all scan tool passenger seat switch parameters listed below are Inactive:
3. Install a 3 A fused jumper wire between the appropriate signal circuit terminal listed below and the ground circuit terminal E.
4. Verify the appropriate scan tool seat switch parameter is Forward/Rearward or UP/Down.
5. Test or replace the S64P Seat Adjuster Switch - Passenger.
Component Testing
Seat Adjuster Switch Test
1. Ignition OFF, disconnect the harness connector at the S64P Seat Adjuster Switch - Passenger.
2. Test for infinite resistance between the ground terminal E and each signal terminal with the switch in the open position.
Replace the S64P Seat Adjuster Switch - Passenger.
3. Test for less than 2 Ω between the ground terminal E and each signal terminal with the appropriate switch in the closed position.
Replace theS64P Seat Adjuster Switch - Passenger.
4. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
DTC B183B or B183C
Diagnostic Instructions
DTC Descriptors
DTC B183B
Seat Lumbar Support Switch Signal Circuit
DTC B183C
Seat Bolster/Massage Switch Signal Circuit
For symptom byte information refer to Symptom Byte List.
Diagnostic Fault Information
1. The seat lumbar support function is inoperative.
2. The seat side bolster/massage function is inoperative.
Circuit/System Description
Ground is supplied to the seat lumbar support and the seat back side bolster switches. Each switch is also supplied with a 5 V reference and signal circuits from the seat memory control module. The reference voltage is applied to a resistive network internal to the switches. When a switch is pressed, the output of the resistive network results in a voltage drop on the signal circuit to the seat memory control module indicating the lumbar, bolster, or massage request. In response to this signal, the seat memory control module sends a LIN serial data message to the seat bolster memory control module commanding it to perform the required pneumatic movements.
Conditions for Running the DTC
Conditions for Setting the DTC
B183B 06
If the seat memory control module detects a short to ground or an open in the seat lumbar support switch signal circuit this DTC will set.
B183B 08
If the seat memory control module detects an invalid signal on the seat lumbar support switch signal circuit this DTC will set.
B183B 59
The seat memory control module detects a stuck lumbar support switch for a given amount of time.
B183C 06
If the seat memory control module detects a short to ground or an open in the seat bolster/massage switch signal circuit this DTC will set.
B183C 08
If the seat memory control module detects an invalid signal on the seat bolster/massage switch signal circuit this DTC will set.
B183C 59
The seat memory control module detects a stuck seat bolster or massage switch for a given amount of time.
Actions Taken When the DTC Sets
B183B 06, B183B 08, or B183B 59
B183C 06, B183C 08, or B183C 59
Conditions for Clearing the DTCs
Reference Information
Schematic Reference
Connector End View Reference
Component Connector End View Index
Description and Operation
Lumbar Support Description and Operation (With Memory Seat A44/A45) or Lumbar Support Description and Operation (Without Memory Seat A44/A45)
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
1. Ignition ON.
2. Verify DTC B183B 59 is not set as a current DTC.
Replace the S65 Seat Lumbar Support Switch.
3. Verify DTC B183C 59 is not set as a current DTC.
Replace the S66 Seat Back Side Bolster Adjuster Switch.
4. Verify DTC B183B 06 or B183B 08 is not set.
Refer to Circuit/System Testing - DTC B183B Lumbar Switch Circuit Test.
5. Verify DTC B183C 06 or B183C 08 is not set.
Refer to Circuit/System Testing - DTC B183C Seat Back Side Bolster Switch Circuit Test.
6. All OK.
Circuit/System Testing
DTC B183B Lumbar Switch Circuit Test
1. Ignition OFF, disconnect the harness connector at the appropriate seat lumbar support switch listed below. 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 1 and ground.
3. Ignition ON.
4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 3 and ground.
5. Test for less than 1 V between the signal circuit terminal 2 and ground.
NOTE: With the seat lumbar support switch disconnected, DTC B183B with symptom byte 06 may already be set. However, the purpose of this test is to verify DTC B183B will set with symptom byte 08 when the signal circuit is shorted to voltage.
6. Install a 3 A fused jumper wire between the 5 V reference circuit terminal 3 and the signal circuit terminal 2.
7. Verify DTC B183B 08 is set.
8. Test or replace the S65 Seat Lumbar Support Switch.
DTC B183C Seat Back Side Bolster Switch Circuit Test
1. Ignition OFF, disconnect the harness connector at the seat back side bolster adjuster switch listed below. 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 1 and ground.
3. Ignition ON.
4. Test for 4.8 - 5.2 V between the 5 V reference circuit terminal 3 and ground.
5. Test for less than 1 V between the signal circuit terminal 2 and ground.
NOTE: With the seat back side bolster adjuster switch disconnected, DTC B183C with symptom byte 06 may already be set. However, the purpose of this test is to verify DTC B183C will set with symptom byte 08 when the signal circuit is shorted to voltage.
6. Install a 3 A fused jumper wire between the 5 V reference circuit terminal 3 and the signal circuit terminal 2.
7. Verify DTC B183C 08 is set.
8. Test or replace the S66 Seat Back Side Bolster Adjuster Switch.
Component Testing
Seat Lumbar Support Switch
1. Ignition OFF, disconnect the harness connector at the S65 Seat Lumbar Support Switch.
2. Test for infinite resistance between the signal terminal 2 and the ground terminal 1 with the switch in the open position.
Replace the S65 Seat Lumbar Support Switch.
3. Test for 252 - 308 Ω between the signal terminal 2 and the 5 V reference terminal 3.
Replace the S65 Seat Lumbar Support Switch.
4. Test for 146 - 178 Ω between the signal terminal 2 and the ground terminal 1 while pressing the lumbar rearward switch.
Replace the S65 Seat Lumbar Support Switch.
5. Test for 459 - 561 Ω between the signal terminal 2 and the ground terminal 1 while pressing the lumbar forward switch.
Replace the S65 Seat Lumbar Support Switch.
6. Test for 1134 - 1386 Ω between the signal terminal 2 and the ground terminal 1 while pressing the lumbar down switch.
Replace the S65 Seat Lumbar Support Switch.
7. Test for 3.02k - 3.7 kΩ between the signal terminal 2 and the ground terminal 1 while pressing the lumbar up switch.
Replace the S65 Seat Lumbar Support Switch.
8. All OK.
Seat Back Side Bolster Switch
1. Ignition OFF, disconnect the harness connector at the S66 Seat Back Side Bolster Adjuster Switch.
2. Test for infinite resistance between the signal terminal 2 and the ground terminal 1 with the switch in the open position.
Replace the S66 Seat Back Side Bolster Adjuster Switch.
3. Test for 252 - 308 Ω between the signal terminal 2 and the 5 V reference terminal 3.
Replace the S66 Seat Back Side Bolster Adjuster Switch.
4. Test for 459 - 561 Ω between the signal terminal 2 and the ground terminal 1 while pressing the seat back side bolster inflate switch.
Replace the S66 Seat Back Side Bolster Adjuster Switch.
5. Test for 1134 - 1386 Ω between the signal terminal 2 and the ground terminal 1 while pressing the seat back side bolster deflate switch.
Replace the S66 Seat Back Side Bolster Adjuster Switch.
6. Test for 3.02k - 3.7 kΩ between the signal terminal 2 and the ground terminal 1 while pressing the massage switch.
Replace the S66 Seat Back Side Bolster Adjuster Switch.
7. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
DTC B2755 or B2765
Diagnostic Instructions
DTC Descriptors
DTC B2755
Seat Memory Select Switch Circuit
DTC B2765
Seat Memory Set Switch Circuit
For symptom byte information refer to Symptom Byte List.
Diagnostic Fault Information
1. Memory recall is inoperative
Circuit/System Description
Low reference is supplied to the seat memory switch from the seat memory control module. When a memory switch is pressed, the signal circuit from the seat memory control module is pulled low through the switch contacts and series of resistors indicating the memory recall request. In response to this signal, the seat memory control module commands the appropriate seat motors to move to the prerecorded seat positions stored in memory.
Conditions for Running the DTC
Conditions for Setting the DTC
B2755 01
If the seat memory control module detects a short to voltage on the memory seat switch signal circuit this DTC will set.
B2755 02
If the seat memory control module detects a short to ground on the memory seat switch signal circuit this DTC will set.
B2755 59
The seat memory control module detects a stuck Memory 1 or Memory 2 switch for a given amount of time.
B2765 59
If the memory set switch signal is active for greater than 15 s this DTC will set.
Actions Taken When the DTC Sets
Conditions for Clearing the DTCs
Reference Information
Schematic Reference
Connector End View Reference
Component Connector End View Index
Description and Operation
Memory Seats Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
1. Ignition ON.
2. Verify the appropriate scan tool Driver or Passenger Seat Memory Recall Switches parameter changes between Inactive and Memory 1 when pressing the memory 1 switch.
Refer to Circuit/System Testing.
3. Verify the appropriate scan tool Driver or Passenger Seat Memory Recall Switches parameter changes between Inactive and Memory 2 when pressing the memory 2 switch.
Refer to Circuit/System Testing.
4. Verify the appropriate scan tool Driver or Passenger Seat Memory Recall Switches parameter changes between Inactive and Exit when pressing the Exit switch.
Refer to Circuit/System Testing.
5. Verify the appropriate scan tool Driver or Passenger Seat Memory Set Switch parameter changes between Inactive and Active when pressing the SET switch.
Refer to Circuit/System Testing.
6. All OK.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate seat memory switch listed below, ignition ON.
2. Press a power seat switch in order to wake up the K40 Seat Memory Control Module.
3. Test for 9 V or greater between each signal circuit terminal listed below and ground:
4. Ignition OFF, disconnect the X6 harness connector at the K40 Seat Memory Control Module, ignition ON.
5. Test for less than 1 V between each signal circuit terminal listed below and ground:
Repair the short to voltage on the circuit.
6. Test or replace the S47 Seat Memory Switch.
Component Testing
Seat Memory Switch
1. Ignition OFF, disconnect the harness connector at the S47 Seat Memory Switch.
2. Test for infinite resistance between each signal terminal listed below and the low reference terminal 1 with the switch in the open position.
Replace the S47 Seat Memory Switch.
3. Test for less than 4 Ω between the signal terminal 5 and the low reference terminal 1 while pressing the memory SET button.
Replace the S47 Seat Memory Switch.
4. Test for 573 - 701 Ω between the signal terminal 6 and the low reference terminal 1 while pressing the memory 1 button.
Replace the S47 Seat Memory Switch.
5. Test for 1800 - 2201 Ω between the signal terminal 6 and the low reference terminal 1 while pressing the memory 2 button.
Replace the S47 Seat Memory Switch.
6. Test for 5.52k - 6.73 kΩ between the signal terminal 6 and the low reference terminal 1 while pressing the Exit button.
Replace the S47 Seat Memory Switch.
7. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
DTC B3920
Diagnostic Instructions
DTC Descriptors
DTC B3920
Seat Motors Group 1 Ground Circuit
For symptom byte information refer to Symptom Byte List.
Diagnostic Fault Information
1. All power seat and memory functions are inoperative.
Circuit/System Description
The seat memory control module controls the seat motors via half bridges that are connected to a power rail internal to the module. The seat memory control module connects all of the motor control circuits on the power rail to a common reference point whenever they are not in operation. The module monitors all seat motor control circuits for a shorted to ground or voltage before enabling any seat motor.
When a power seat switch is pressed or when a memory recall is requested, each seat motor receives battery voltage and ground from the seat memory control module via the motor control circuits. All motors are reversible, so the direction the motor rotates depends on which control circuit voltage is applied and which control circuit ground is applied. When the switch is operated in the opposite direction, the module reverses the polarity and applies voltage and ground to the opposite circuits to move the seat in the opposite direction.
Conditions for Running the DTC
Conditions for Setting the DTC
B3920 00
Current out of the module does not match the current returning to the module from 1.5 - 5 A.
B3920 01
The voltage on any power rail 1 motor control circuit exceeds 2.78 V for 100 ms.
B3920 02
The voltage on any power rail 1 motor control circuit is below 1.47 V for 100 ms.
B3920 0B
The differential current measured through the high and low side of the power rail is within tolerance of each other, but the absolute current or an over-current has exceeded the maximum value.
Action Taken When the DTC Sets
The seat memory control module will not allow operation of any motor on the power rail for which the DTC was set.
Conditions for Clearing the DTC
Reference Information
Schematic Reference
Connector End View Reference
Component Connector End View Index
Description and Operation
Memory Seats Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Testing
B3920 01 or B3920 02
1. Ignition OFF, disconnect the X3 harness connector at the appropriate seat memory control module listed below:
2. Test for infinite resistance between each control circuit terminal listed below and ground:
Repair the short to ground on the circuit.
3. Ignition ON.
4. Test for less than 1 V between each control circuit terminal listed below and ground:
Repair the short to voltage on the circuit.
5. Replace the K40 Seat Memory Control Module.
B3920 00 or B3920 0B
1. Ignition ON.
2. Clear the current and history DTC.
3. Determine which motor set this DTC by operating each seat motor listed below one at a time in both directions. Check for the DTC to set between each motor test.
4. Ignition OFF, disconnect the harness connector at the seat motor for which the DTC set, ignition ON.
5. Clear the DTC.
6. Verify that DTC B3920 00 or B3920 0B does not set while operating the seat motor adjuster switch in both directions.
7. Test or replace the seat motor.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
DTC B392B
Diagnostic Instructions
DTC Descriptors
DTC B392B 00
Seat Lumbar/Bolster Pump
Diagnostic Fault Information
1. The lumbar, bolster and massage functions are inoperative
Circuit/System Description
When a seat lumbar, bolster, or massage function is commanded ON, the seat bolster memory control module applies battery voltage and a low side drive pulse width modulated (PWM) signal through their respective control circuits to the seat lumbar/bolster pump. The logic in the pump interprets this signal and pump runs to inflate the lumbar/bolster bladders until the switch is released.
Conditions for Running the DTC
Conditions for Setting the DTC
The seat bolster memory control module detects a short to ground on the lumbar/bolster pump voltage control circuit.
Action Taken When the DTC Sets
All lumbar, bolster, and massage functions are inoperative.
Conditions for Clearing the DTC
Reference Information
Schematic Reference
Connector End View Reference
Component Connector End View Index
Description and Operation
Lumbar Support Description and Operation (With Memory Seat A44/A45) or Lumbar Support Description and Operation (Without Memory Seat A44/A45)
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Testing
1. Ignition OFF, all vehicle systems OFF, disconnect the harness connector at the appropriate seat lumbar/bolster pump listed below:
2. Test for less than 10 Ω between the low reference circuit terminal 2 and ground.
3. Connect a test lamp between the control circuit terminal 1 and ground, ignition ON.
4. Verify the test lamp turns ON after pressing and holding the lumbar forward switch.
5. Test or replace the G31 Seat Lumbar/Bolster Pump.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
DTC B392C
Diagnostic Instructions
DTC Descriptors
DTC B392C 39
Seat Bolster Memory Control Module Internal Malfunction
Circuit/System Description
The seat memory control module detects an internal electronic fault in the seat bolster memory control module. No external circuits are involved.
Conditions for Running the DTC
Ignition ON.
Conditions for Setting the DTC
The control module detects an internal fault.
An internal electronic fault in the seat bolster memory control module will set this DTC.
Action Taken When the DTC Sets
All lumbar/bolster functions will be inoperative.
Conditions for Clearing the DTC
Reference Information
Schematic Reference
Connector End View Reference
Component Connector End View Index
Description and Operation
Lumbar Support Description and Operation (With Memory Seat A44/A45) or Lumbar Support Description and Operation (Without Memory Seat A44/A45)
Electrical Information Reference
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
DTC B392C
1. Ignition ON.
2. Verify DTC B392C is not set.
Replace the appropriate K134 Seat Bolster Memory Control Module.
3. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Control Module References for K134D Seat Bolster Memory Control Module - Driver or K134P Seat Bolster Memory Control Module - Passenger replacement, programming and setup.
Symptoms - Power Seats
NOTE: The following steps must be completed before using the symptom tables.
1. Perform the Diagnostic System Check - Vehicle before using the Symptom Tables in order to verify that all of the following are true:
2. Review the system operation in order to familiarize yourself with the system functions. Refer to the following system descriptions:
Visual/Physical Inspection
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 a symptom diagnostic procedure from the following list in order to diagnose the symptom:
Lumbar/Bolster/Massage Malfunction (AVK with AF6 or AVU with AKE)
Diagnostic Instructions
Diagnostic Fault Information
1. The lumbar, bolster, and massage functions are inoperative
Circuit/System Description
Ground is supplied to the driver and passenger seat lumbar support and the seat back side bolster switches. Each switch is also supplied with a 5 V reference and signal circuits from the seat memory control module. The reference voltage is applied to a resistive network internal to the switches. When a switch is pressed, the output of the resistive network results in a voltage drop on the signal circuit to the seat memory control module indicating the lumbar, bolster, or massage request. In response to this signal, the seat memory control module sends a LIN serial data message to the seat massage valve assembly commanding it to perform the required pneumatic movements.
The seat massage valve assembly contains the electronic circuitry for executing the commanded pneumatic seat adjustments, air direction solenoids, pressure sensors for storing air bladder pressures, and outputs which supplies battery power and a low side drive pulse width modulated (PWM) signal to the external seat air pump motor when any of the air bladders require inflating.
Reference Information
Schematic Reference
Connector End View Reference
Component Connector End View Index
Description and Operation
Lumbar Support Description and Operation (With Memory Seat A44/A45) or Lumbar Support Description and Operation (Without Memory Seat A44/A45)
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
1. Ignition ON.
2. Verify the appropriate scan tool Driver or Passenger Lumbar Support Horizontal Switch parameter changes between Inactive and Forward/Rearward when pressing the lumbar horizontal switch in the Forward and Rearward directions.
Refer to DTC B183B or B183C.
3. Verify the scan tool Lumbar Support Vertical Switch parameter changes between Inactive and Up/Down when pressing the lumbar vertical switch in the Up and Down directions.
Test or replace the S65 Seat Lumbar Support Switch.
4. Verify the scan tool Seat Back Side Bolster Switch parameter changes between Inactive and Inflate/Deflate when pressing the bolster switch in both directions.
Refer to DTC B183B or B183C.
5. Verify the scan tool Seat Massage Switch parameter changes between Inactive and Active when pressing the seat massage switch.
Test or replace the S66 Seat Back Side Bolster Adjuster Switch.
6. Refer to Circuit/System Testing.
Circuit/System Testing
1. Ignition OFF, all vehicle systems OFF, disconnect the harness connector at the appropriate seat bolster memory control module listed below. 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 3 and ground.
3. Ignition ON.
4. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.
5. Ignition OFF, connect the harness connector at the K134 Seat Bolster Memory Control Module and disconnect the harness connector at the G31 Seat Lumbar/Bolster Pump.
6. Test for less than 10 Ω between the low reference circuit terminal 2 and ground.
7. Connect a test lamp between the control circuit terminal 1 and ground, ignition ON.
8. Verify the test lamp turns ON when pressing the lumbar forward switch.
9. Test or replace the G31 Seat Lumbar/Bolster Pump.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Lumbar/Bolster/Massage Malfunction (AVK without AF6 or AVU without AKE)
Diagnostic Instructions
Diagnostic Fault Information
1. The seat lumbar support functions are inoperative
2. The seat lumbar support pump is always ON
Circuit/System Description
The seat lumbar support valve assembly supplies the seat lumbar support switch with a signal and low reference circuits. When a lumbar switch is pressed, the signal circuit from the seat lumbar support valve assembly is pulled low through the switch contacts and series of resistors indicating the lumbar support request. In response to this request, the lumbar adjuster valve assembly energizes its internal inflate solenoid and applies battery voltage through the lumbar support pump control circuit to the pump. The pump runs to inflate the appropriate support bladder until the switch is released.
Reference Information
Schematic Reference
Connector End View Reference
Component Connector End View Index
Description and Operation
Lumbar Support Description and Operation (With Memory Seat A44/A45) or Lumbar Support Description and Operation (Without Memory Seat A44/A45)
Electrical Information Reference
Circuit/System Testing
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate seat lumbar support valve assembly listed below. 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.
3. Ignition ON.
4. Verify a test lamp illuminates between the B+ circuit terminal 1 and ground.
5. Ignition OFF and all vehicle systems OFF, connect the harness connector at the Q51 Seat Lumbar Support Valve Assembly and disconnect the harness connector at the S65 Seat Lumbar Support Switch. It may take up to 2 min for all vehicle systems to power down.
6. Test for less than 10 Ω between the low reference circuit terminal 1 and ground.
7. Ignition ON.
8. Test for 4.8 - 5.2 V between the signal circuit terminal 2 and ground.
9. Ignition OFF, connect the harness connector at the S65 Seat Lumbar Support Switch and disconnect the harness connector at the Q51 Seat Lumbar Support Valve Assembly.
10. Connect a DDM between the signal circuit terminal 4 and the low reference circuit terminal 5.
11. Test for the resistance values listed below while pressing the appropriate S65 Seat Lumbar Support Switch.
Test or replace the S65 Seat Lumbar Support Switch.
12. Ignition OFF, connect the harness connector at the Q51 Seat Lumbar Support Valve Assembly and disconnect the harness connector at the G31 Seat Lumbar/Bolster Pump.
13. Test for less than 10 Ω between the ground circuit terminal 2 and ground.
14. Connect a test lamp between the control circuit terminal 1 and ground, ignition ON.
15. Verify the test lamp turns ON and OFF when pressing and releasing the lumbar forward switch.
16. Test or replace the G31 Seat Lumbar/Bolster Pump.
Component Testing
Seat Lumbar Support Switch
1. Ignition OFF, disconnect the harness connector at the appropriate S65 Seat Lumbar Support Switch.
2. Test for infinite resistance between the signal terminal 2 and the low reference terminal 1 with the switch in the open position.
Replace the S65 Seat Lumbar Support Switch.
3. Test for 146 - 178 Ω between the signal terminal 2 and the low reference terminal 1 while pressing the lumbar forward switch.
Replace the S65 Seat Lumbar Support Switch.
4. Test for 459 - 561 Ω between the signal terminal 2 and the low reference terminal 1 while pressing the lumbar rearward switch.
Replace the S65 Seat Lumbar Support Switch.
5. Test for 1134 - 1386 Ω between the signal terminal 2 and the low reference terminal 1 while pressing the lumbar down switch.
Replace the S65 Seat Lumbar Support Switch.
6. Test for 3.02k - 3.7 kΩ between the signal terminal 2 and the low reference terminal 1 while pressing the lumbar up switch.
Replace the S65 Seat Lumbar Support Switch.
7. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Lumbar/Bolster/Massage Malfunction (AL9 or AT9)
Diagnostic Instructions
Diagnostic Fault Information
1. The power seat and the lumbar support functions are inoperative
2. The lumbar support is inoperative
Circuit/System Description
Battery voltage is supplied at all times to the seat adjuster switch through a 10 A fuse located in the underhood fuse block. When a lumbar switch is pressed to inflate the lumbar support, battery voltage is applied through the switch contacts and the inflate control circuit to the seat lumbar support valve assembly. In response to this signal, the valve assembly energizes its internal inflate solenoid and runs to inflate the lumbar bladder until the switch is released. When the switch is pressed to deflate the lumbar support, battery voltage is applied through the switch contacts and the deflate signal circuit to the seat lumbar support valve assembly. The valve assembly energizes its internal deflate solenoid and air is released from the bladder until the switch is released.
Reference Information
Schematic Reference
Connector End View Reference
Component Connector End View Index
Description and Operation
Lumbar Support Description and Operation (With Memory Seat A44/A45) or Lumbar Support Description and Operation (Without Memory Seat A44/A45)
Electrical Information Reference
Circuit/System Verification
1. Ignition ON.
2. Verify the seat lumbar operates in both directions - Forward/Rearward.
Refer to Circuit/System Testing
3. All OK.
Circuit/System Testing
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate seat lumbar support switch listed below. 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 E and ground.
3. Ignition ON.
4. Verify a test lamp illuminates between the B+ circuit terminal G and ground.
5. Ignition OFF, connect the harness connector at the S65 Seat Lumbar Support Switch and disconnect the harness connector at the Q51 Seat Lumbar Support Valve Assembly.
6. Connect a test lamp between control circuit terminal 1 and control circuit terminal 2, ignition ON.
7. Verify the test lamp turns ON when pressing the lumbar switch in the Forward and Rearward directions.
8. Test or replace the Q51 Seat Lumbar Support Valve Assembly.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Memory Seat Feature Malfunction
Diagnostic Instructions
Diagnostic Fault Information
1. Memory seat feature is inoperative
Circuit/System Description
Low reference is supplied to the seat memory switch from the seat memory control module. When a memory switch is pressed, the signal circuit from the seat memory control module is pulled low through the switch contacts and series of resistors indicating the memory recall request. In response to this signal, the seat memory control module commands the appropriate seat motors to move to the prerecorded seat positions stored in memory.
Diagnostic Aids
Reference Information
Schematic Reference
Connector End View Reference
Component Connector End View Index
Description and Operation
Memory Seats Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
1. Ignition ON.
2. Verify that all manual power seat functions operate when being controlled by the power seat adjuster switches.
Refer to Power Seat Malfunction (Driver or Passenger without Memory A44 or A45), Power Seat Malfunction (Driver Seat with Memory A45), or Power Seat Malfunction (Passenger Seat with Memory A44)
3. Refer to Circuit/System Testing.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate seat memory switch listed below:
2. Test for less than 30 Ω between the low reference circuit terminal 1 and ground.
3. Ignition ON, press a power seat switch in order to wake up the K40 Seat Memory Control Module.
4. Test for 9 V or greater between each signal circuit terminal listed below and ground:
5. Ignition OFF, disconnect the X6 harness connector at the K40 Seat Memory Control Module, ignition ON.
6. Test for less than 1 V between each signal circuit terminal listed below and ground:
Repair the short to voltage on the circuit.
7. Test or replace the S47 Seat Memory Switch.
Component Testing
Seat Memory Switch
1. Ignition OFF, disconnect the harness connector at the S47 Seat Memory Switch.
2. Test for infinite resistance between each signal terminal listed below and the low reference terminal 1 with the switch in the open position.
Replace the S47 Seat Memory Switch.
3. Test for less than 4 Ω between the signal terminal 5 and the low reference terminal 1 while pressing the memory SET button.
Replace the S47 Seat Memory Switch.
4. Test for 573 - 701 Ω between the signal terminal 6 and the low reference terminal 1 while pressing the memory 1 button.
Replace the S47 Seat Memory Switch.
5. Test for 1800 - 2201 Ω between the signal terminal 6 and the low reference terminal 1 while pressing the memory 2 button.
Replace the S47 Seat Memory Switch.
6. Test for 5.52k - 6.73 kΩ between the signal terminal 6 and the low reference terminal 1 while pressing the Exit button.
Replace the S47 Seat Memory Switch.
7. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Power Folding Seat Malfunction
Diagnostic Instructions
Diagnostic Fault Information
1. The left rear power folding seat is inoperative.
2. The right rear power folding seat is inoperative.
Circuit/System Description
Battery voltage is supplied at all times to the folding seat control switch through a 15 A fuse located in the instrument panel fuse block. When the folding seat control switch is pressed to fold the seat back cushion forward, battery voltage is applied through the switch contacts and the folding seat motor control circuit to the motor. The motor runs in order to fold the seat back cushion forward.
Reference Information
Schematic Reference
Rear Seat Wiring Schematics
Connector End View Reference
Component Connector End View Index
Description and Operation
Power Seats System Description and Operation
Electrical Information Reference
Circuit/System Testing
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate folding seat motor listed below:
2. Test for less than 10 Ω between the ground circuit terminal and ground.
3. Connect a test lamp between the control circuit terminal 1 and the ground circuit terminal 2, ignition ON.
4. Verify the test lamp does not turn ON when commanding the M19 Folding Seat Motor froward using the S20 Folding Seat Control Switch.
5. Test or replace the M19 Folding Seat Motor.
6. Ignition OFF, disconnect the harness connector at the appropriate folding seat control switch listed below:
7. Ignition ON.
8. Verify a test lamp illuminates between the B+ circuit terminal 5 and ground.
9. Test for infinite resistance between the control circuit and ground.
10. Test for less than 2 Ω in the control circuit end to end.
11. Test or replace the S20 Folding Seat Control Switch.
Component Testing
Folding Seat Control Switch
1. Ignition OFF, disconnect the harness connector at the S20 Folding Seat Control Switch.
2. Test for infinite resistance between the B+ terminal 5 and the control terminal 1 with the switch in the open position.
Replace the S20 Folding Seat Control Switch.
3. Test for less than 2 Ω between the B+ terminal 5 and each control terminal 1 with the switch in the closed position.
Replace the S20 Folding Seat Control Switch.
4. All OK.
Folding Seat Motor
1. Ignition OFF, disconnect the harness connector at the M19 Folding Seat Motor.
NOTE: When performing the following tests, make sure that the seat is not already in the position the test is attempting to produce.
2. Install a 30 A fused jumper wire between control terminal 1 and 12 V.
3. Momentarily install a jumper wire between control terminal 2 and ground. The seat motor should momentarily perform the FORWARD function.
Replace the motor.
4. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Power Seat Malfunction (Driver or Passenger without Memory A44 or A45)
Diagnostic Instructions
Diagnostic Fault Information
1. All power seat motors are inoperative
2. The seat front vertical motor is inoperative
3. The seat horizontal motor is inoperative
4. The seat rear vertical motor is inoperative
5. The seat recline motor is inoperative
6. The seat motor operates until maximum travel is reached
Circuit/System Description
The driver and passenger power seats are completely controlled through the seat adjuster switch. Battery voltage is supplied at all times to the seat adjuster switch through a 30 A fuse located in the underhood fuse block. When the seat switches are in an inactive state, the switch contacts are closed to the switch ground circuit.
All seat motors are reversible. For example, when the seat horizontal forward switch is pressed to move the entire seat forward, battery voltage is applied through the switch contacts and the seat horizontal motor rearward control circuit to the motor. With the horizontal motor rearward switch contacts closed to the switch ground circuit, the motor runs in order to drive the entire seat forward until the switch is released. Moving the entire seat rearward works similarly to moving the entire seat forward, except that battery positive voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction. All seat motors are powered this way.
Reference Information
Schematic Reference
Connector End View Reference
Component Connector End View Index
Description and Operation
Power Seats System Description and Operation
Electrical Information Reference
Circuit/System Verification
1. Verify the appropriate driver or passenger seat directional motors listed below operate while operating the seat switches in both directions.
Refer to Circuit/System Testing - Seat Adjuster Switch Circuit Test.
Refer to Circuit/System Testing - Seat Motor Circuit Test.
2. All OK.
Circuit/System Testing
Seat Adjuster Switch Circuit Test
1. Ignition OFF, disconnect the harness connector at the appropriate seat adjuster switch listed below:
2. Test for less than 10 Ω between the ground circuit terminal B and ground.
3. Ignition ON.
4. Verify a test lamp illuminates between the B+ circuit terminal E and ground.
5. Test or replace the S64 Seat Adjuster Switch.
Seat Motor Circuit Test
1. Ignition OFF, disconnect the harness connector at the appropriate seat motor listed below:
2. Ignition on.
3. Test for less than 1 V between each control circuit and ground.
4. Connect a test lamp between control circuit terminal 1 and control circuit terminal 3, ignition ON.
5. Verify the test lamp turns ON when commanding the seat motor Up and Down or Forward and Rearward using the seat adjuster switch.
6. Test or replace the seat motor.
Component Testing
Seat Adjuster Switch Test
1. Ignition OFF, disconnect the harness connector at the S64 Seat Adjuster Switch.
2. Test for infinite resistance between the B+ terminal E and each control terminal with the switch in the open position.
Replace the S64 Seat Adjuster Switch.
3. Test for less than 2 Ω between the B+ terminal E and each control terminal with the appropriate switch in the closed position.
Replace the S64 Seat Adjuster Switch.
4. Test for less than 2 Ω between the ground terminal B and each control terminal with the switch in the open position.
Replace the S64 Seat Adjuster Switch.
5. All OK.
Seat Motor
1. Ignition OFF, disconnect the harness connector at the appropriate seat motor listed below:
NOTE: When performing the following tests, make sure that the seat is not already in the position the test is attempting to produce.
2. Install a 30 A fused jumper wire between control terminal 1 and 12 V.
3. Momentarily install a jumper wire between control terminal 3 and ground. The seat motor should momentarily perform the appropriate FORWARD/ REARWARD/ UP/ DOWN function.
Replace the motor.
4. Reverse the jumper wires; the motor should perform FORWARD/ REARWARD/ UP/ DOWN function.
Replace the motor.
5. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Power Seat Malfunction (Driver Seat with Memory A45)
Diagnostic Instructions
Diagnostic Fault Information
1. All power seat motors are inoperative
2. The seat front vertical motor is inoperative
3. The seat horizontal motor is inoperative
4. The seat rear vertical motor is inoperative
5. The seat recline motor is inoperative
Circuit/System Description
Battery voltage is supplied at all times to the seat memory control module through a 5 A fuse located in the underhood fuse block. This voltage is used by the module for logic power. Battery positive voltage is also supplied at all times to the seat memory control module through a 30 A fuse also located in the underhood fuse block. This voltage is connected to a power rail internal to the seat memory control module and is used to drive all driver power seat motors. Each seat motor is controlled by the seat memory control module by applying power and ground through the control circuits to the motor.
All motors are reversible. For example, when the seat switch is operated to move the entire seat forward, the switch signal circuit from the seat memory control module is pulled low indicating the entire seat forward command. In response to this signal, the seat memory control module applies battery voltage through the driver seat horizontal motor forward control circuit and ground through the driver seat horizontal motor rearward control circuit to the motor. The motor runs to drive the entire seat forward until the switch is released. Moving the entire seat rearward works similarly to moving the entire seat forward, except that battery positive voltage and ground are applied on the opposite circuits causing the motor to run in the opposite direction. All driver power seat motors are powered this way.
Reference Information
Schematic Reference
Driver Seat Wiring Schematics
Connector End View Reference
Component Connector End View Index
Description and Operation
Memory Seats Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
1. Ignition ON.
2. Verify the scan tool seat switch parameters listed below change between Inactive and Forward/Rearward or Up/Down when pressing the appropriate switch.
Refer to Circuit/System Testing - Seat Adjuster Switch Circuit Test
3. Verify the seat directional motors listed below operate when pressing the appropriate seat switches in both directions.
Refer to Circuit/System Testing - Seat Motor Control Circuit Test.
4. All OK.
Circuit/System Testing
Seat Adjuster Switch Circuit Test
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S64D Seat Adjuster Switch - Driver. 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 E and ground.
3. Install a 3 A fused jumper wire between the ground circuit terminal E and the appropriate signal circuit terminal listed below, ignition ON.
4. Verify the appropriate scan tool seat switch parameter is Forward/Rearward or UP/Down.
5. Test or replace the S64D Seat Adjuster Switch - Driver.
Seat Motor Control Circuit Test
1. Ignition OFF, disconnect the X2 harness connector at the K40D Seat Memory Control Module - Driver.
2. Test for less than 10 Ω between ground circuit terminal 5 and ground.
3. Ignition OFF, disconnect the X1 harness connector at the K40D Seat Memory Control Module - Driver, ignition ON.
4. Verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.
5. Ignition OFF, connect the X1 and X2 harness connectors at the K40D Seat Memory Control Module - Driver and disconnect the harness connector at the appropriate seat motor listed below:
6. Connect a test lamp between control circuit terminal 1 and control circuit terminal 3, ignition ON.
NOTE: Once a seat motor is commanded On using the scan tool, the seat function may not work using the seat adjuster switch until you back out of the scan tool Control Functions menu.
7. Verify the test lamp turns ON when commanding the seat motor in the Up/Down or Forward/Rearward states with a scan tool.
8. Test or replace the seat motor.
Component Testing
Seat Adjuster Switch Test
1. Ignition OFF, disconnect the harness connector at the S64D Seat Adjuster Switch - Driver.
2. Test for infinite resistance between the ground terminal E and each signal terminal with the switch in the open position.
Replace the S64D Seat Adjuster Switch - Driver.
3. Test for less than 2 Ω between the ground terminal E and each signal terminal with the appropriate switch in the closed position.
Replace the S64D Seat Adjuster Switch - Driver.
4. All OK.
Seat Motor
1. Ignition OFF, disconnect the harness connector at the appropriate seat motor listed below:
NOTE: When performing the following tests, make sure that the seat is not already in the position the test is attempting to produce.
2. Install a 30 A fused jumper wire between control terminal 1 and 12 V.
3. Momentarily install a jumper wire between control terminal 3 and ground. The seat motor should momentarily perform the appropriate FORWARD/ REARWARD/ UP/ DOWN function.
Replace the seat motor.
4. Reverse the jumper wires; the motor should perform FORWARD/ REARWARD/ UP/ DOWN function.
Replace the seat motor.
5. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
Power Seat Malfunction (Passenger Seat with Memory A44)
Diagnostic Instructions
Diagnostic Fault Information
1. All power seat motors are inoperative
2. The seat front vertical motor is inoperative
3. The seat horizontal motor is inoperative
4. The seat rear vertical motor is inoperative
5. The seat recline motor is inoperative
Circuit/System Description
Battery voltage is supplied at all times to the seat memory control module through a 5 A fuse located in the underhood fuse block. This voltage is used by the module for logic power. Battery positive voltage is also supplied at all times to the seat memory control module through a 30 A fuse also located in the underhood fuse block. This voltage is connected to a power rail internal to the seat memory control module and is used to drive all power seat motors. Each seat motor is controlled by the seat memory control module by applying power and ground through the control circuits to the motor.
All motors are reversible. For example, when the seat switch is operated to move the entire seat forward, the switch signal circuit from the seat memory control module is pulled low indicating the entire seat forward command. In response to this signal, the seat memory control module applies battery voltage through the seat horizontal motor forward control circuit and ground through the seat horizontal motor rearward control circuit to the motor. The motor runs to drive the entire seat forward until the switch is released. Moving the entire seat rearward works similarly to moving the entire seat forward, except that battery positive voltage and ground are applied on the opposite circuits causing the motor to run in the opposite direction. All power seat motors are powered this way.
Reference Information
Schematic Reference
Passenger Seat Wiring Schematics
Connector End View Reference
Component Connector End View Index
Description and Operation
Memory Seats Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information.
Circuit/System Verification
1. Ignition ON.
2. Verify the scan tool seat switch parameters listed below change between Inactive and Forward/Rearward or Up/Down when pressing the appropriate switch.
Refer to Circuit/System Testing - Seat Adjuster Switch Circuit Test
3. Verify the seat directional motors listed below operate when pressing the appropriate seat switches in both directions.
Refer to Circuit/System Testing - Seat Motor Control Circuit Test.
4. All OK.
Circuit/System Testing
Seat Adjuster Switch Circuit Test
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S64P Seat Adjuster Switch - Passenger. 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 E and ground.
3. Install a 3 A fused jumper wire between the ground circuit terminal E and the appropriate signal circuit terminal listed below, ignition ON.
4. Verify the appropriate scan tool seat switch parameter is Forward/Rearward or UP/Down.
5. Test or replace the S64P Seat Adjuster Switch - Passenger.
Seat Motor Control Circuit Test
1. Ignition OFF, disconnect the X2 harness connector at the K40P Seat Memory Control Module - Passenger.
2. Test for less than 10 Ω between ground circuit terminal 5 and ground.
3. Ignition OFF, disconnect the X1 harness connector at the K40P Seat Memory Control Module - Passenger, ignition ON.
4. Verify that a test lamp illuminates between the B+ circuit terminal 2 and ground.
5. Ignition OFF, connect the X1 and X2 harness connectors at the K40P Seat Memory Control Module - Passenger and disconnect the harness connector at the appropriate seat motor listed below:
6. Connect a test lamp between control circuit terminal 1 and control circuit terminal 3, ignition ON.
NOTE: Once a seat motor is commanded On using the scan tool, the seat function may not work using the seat adjuster switch until you back out of the scan tool Control Functions menu.
7. Verify the test lamp turns ON when commanding the seat motor in the Up/Down or Forward/Rearward states with a scan tool.
8. Test or replace the seat motor.
Component Testing
Seat Adjuster Switch Test
1. Ignition OFF, disconnect the harness connector at the S64P Seat Adjuster Switch - Passenger.
2. Test for infinite resistance between the ground terminal E and each signal terminal with the switch in the open position.
Replace the S64P Seat Adjuster Switch - Passenger.
3. Test for less than 2 Ω between the ground terminal E and each signal terminal with the appropriate switch in the closed position.
Replace the S64P Seat Adjuster Switch - Passenger.
4. All OK.
Seat Motor
1. Ignition OFF, disconnect the harness connector at the appropriate seat motor listed below:
NOTE: When performing the following tests, make sure that the seat is not already in the position the test is attempting to produce.
2. Install a 30 A fused jumper wire between control terminal 1 and 12 V.
3. Momentarily install a jumper wire between control terminal 3 and ground. The seat motor should momentarily perform the appropriate FORWARD/ REARWARD/ UP/ DOWN function.
Replace the seat motor.
4. Reverse the jumper wires; the motor should perform FORWARD/ REARWARD/ UP/ DOWN function.
Replace the seat motor.
5. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.