Chevrolet Trax: Power seat malfunction (with memory A45)

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 Fault Information

Circuit/System Description

Battery voltage is supplied at all times to the seat memory control module through a 25 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 located in the rear body fuse block.

This voltage is connected to a power rail internal to the seat memory control module and is used to drive the power seat motors and the seat heater elements on vehicles equipped with heated seats. Each seat motor is controlled by the seat memory control module through 2 motor control circuits. The seat memory control module connects all motor control circuits on the power rail to a common reference point whenever they are not in operation. This reference point is biased to approximately 2.5 V. The seat memory control module checks to see if the reference voltage is shorted to ground or battery before enabling any of the seat motors.

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.

Reference Information

Schematic Reference

Driver Seat Schematics (Encore), Driver Seat Schematics (Trax)

Connector End View Reference

WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - ENCORE WIRING SYSTEMS AND POWER MANAGEMENT - COMPONENT CONNECTOR END VIEWS - INDEX - TRAX

Description and Operation

Memory Seats 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 scan tool seat switch parameters listed below change between Inactive and Forward/Rearward or Up/Down when pressing the appropriate switch.

• Driver Seat Horizontal Switch
• Driver Seat Cushion Front Vertical Switch
• Driver Seat Cushion Rear Vertical Switch

If the parameter does not change

Refer to Circuit/System Testing - Driver Seat Adjuster Switch Circuit Test.

If the parameter changes

3. Verify the seat directional motors listed below operate while operating the appropriate driver seat switches in both directions.

• M50D Seat Front Vertical Motor - Driver
• M51D Seat Horizontal Motor - Driver
• M55D Seat Rear Vertical Motor - Driver

If any seat motor does not operate

Refer to Circuit/System Testing - Seat Motor Control Circuit Test.

If all seat motors operate

4. All OK.

Circuit/System Testing

Driver 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 ohms between the ground circuit terminal D and ground.

If 10 ohms or greater

1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.

If less than 10 ohms

3. Verify that all scan tool driver seat switch parameters listed below are Inactive:

• Driver Seat Cushion Front Vertical Switch
• Driver Seat Cushion Rear Vertical Switch
• Driver Seat Horizontal Switch

If not Inactive

1. Ignition OFF, disconnect the harness connector at the K40 Seat Memory Control Module.
2. Test for infinite resistance between the appropriate signal circuit terminal listed below and ground:

• Front vertical up switch terminal G
• Front vertical down switch terminal E
• Rear vertical up switch terminal H
• Rear vertical down switch terminal A
• Horizontal forward switch terminal F
• Horizontal rearward switch terminal C

If less than infinite resistance, repair the short to ground on the circuit.

If infinite resistance, replace the K40 Seat Memory Control Module.

If Inactive

4. Install a 3 A fused jumper wire between the appropriate signal circuit terminal listed below and the ground circuit terminal D.

• Front vertical up switch terminal G
• Front vertical down switch terminal E
• Rear vertical up switch terminal H
• Rear vertical down switch terminal A
• Horizontal forward switch terminal F
• Horizontal rearward switch terminal C

5. Verify the scan tool seat switch parameter is Forward/Rearward or UP/Down.

If not Forward/Rearward or UP/Down

1. Ignition OFF, disconnect the harness connector at the K40 Seat Memory Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit terminal and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V

3. Ignition OFF.
4. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K40 Seat Memory Control Module.

If Forward/Rearward or UP/Down

6. Test or replace the S64D Driver Seat Adjuster Switch.

Seat Motor Control Circuit Test

1. Ignition OFF, disconnect the X4 harness connector at the K40 Seat Memory Control Module.
2. Test for less than 10 ohms between the ground circuit terminal 6 and ground.

If 10 ohms or greater

1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.

If less than 10 ohms

3. Ignition ON.
4. Verify that a test lamp illuminates between the B+ circuit terminal 5 and ground.

If the test lamp does not illuminate

1. Ignition OFF.
2. Test for infinite resistance between the B+ circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

3. Test for less than 2 ohms in the B+ circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, verify the fuse is not open and there is voltage at the fuse.

If the test lamp illuminates

5. Ignition OFF, connect the X4 harness connector at the K40 Seat Memory Control Module and disconnect the harness connector at the appropriate seat motor listed below:

• M50D Seat Front Vertical Motor - Driver
• M51D Seat Horizontal Motor - Driver
• M55D Seat Rear Vertical Motor - Driver

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 illuminates when commanding the seat motor in the Up/Down or Forward/Rearward states with a scan tool.

If the test lamp does not illuminate during either of the commands

1. Ignition OFF, disconnect the X4 harness connector at the K40 Seat Memory Control Module.
2. Test for infinite resistance between each control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance

3. Test for less than 2 ohms in each control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K40 Seat Memory Control Module.

If the test lamp illuminates during each of the commands

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 D and each signal terminal with the switch in the open position.

If less than infinite resistance

Replace the S64D Seat Adjuster Switch - Driver.

If infinite resistance

3. Test for less than 2 ohms between the ground terminal D and each signal terminal with the appropriate switch in the closed position.

If 2 ohms or greater

Replace the S64D Seat Adjuster Switch - Driver.

If less than 2 ohms

4. All OK.

Seat Motor

1. Ignition OFF, disconnect the harness connector at the appropriate seat motor listed below:

• M50D Seat Front Vertical Motor - Driver
• M51D Seat Horizontal Motor - Driver
• M55D Seat Rear Vertical Motor - Driver

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.

If the motor does not perform the FORWARD/ REARWARD/ UP/ DOWN function

Replace the motor.

If the motor performs the FORWARD/ REARWARD/ UP/ DOWN function

4. Reverse the jumper wires; the motor should perform FORWARD/ REARWARD/ UP/ DOWN function.

If the motor does not perform the FORWARD/ REARWARD/ UP/ DOWN function

Replace the motor.

If the motor performs the FORWARD/ REARWARD/ UP/ DOWN function

5. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair

• Driver or Passenger Seat Adjuster Switch Replacement
• Front Seat Tilt Adjuster Actuator Replacement
• Driver or Passenger Seat Vertical Adjuster Actuator Replacement
• Front Seat Adjuster Actuator Replacement
• Control Module References for K40 Seat Memory Control Module replacement, programming and setup

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