FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
Courtesy of Operation CHARM: Car repair manuals for everyone.
Home >> Cadillac >> 2013 >> XTS AWD V6-3.6L >> Repair and Diagnosis >> Body and Frame >> Seats >> Testing and Inspection >> Symptom Related Diagnostic Procedures >> Lumbar Support Malfunction (With Memory A45)

Lumbar Support Malfunction (With Memory A45)




Lumbar Support Malfunction (With Memory A45)

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information






Circuit/System Description

The seat memory control module supplies a reference voltage to each signal circuit of the driver seat lumbar switch. When the lumbar switches are pressed, the appropriate signal circuit from the seat memory control module is pulled low through the switch contacts indicating the power lumbar command. The seat memory control module then applies battery voltage through the appropriate lumbar control circuits to the lumbar support control module. The lumbar module then directs this voltage to the appropriate lumbar motor move in response to the switch signals.

Reference Information

Schematic Reference

* Driver Seat Schematics Driver Seat Schematics

* Passenger Seat Schematics Passenger Seat Schematics

Connector End View Reference

Component Connector End Views Fuel Pump and Level Sensor Assembly

Description and Operation

Lumbar Support Description and Operation (Without Memory A45) Lumbar Support (Without Memory A45)Lumbar Support Description and Operation (With Memory A45) Lumbar Support (With Memory A45)

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.

2. Verify that all power seat functions operate when being controlled by the S64 Seat Adjuster Switches.

• If any power seat function does not operate
Refer to Power Seat Malfunction (Without Memory A45) Power Seat Malfunction (Without Memory A45)Power Seat Malfunction (With Memory A45) Power Seat Malfunction (With Memory A45).

• If all power seat functions operate

3. Verify the scan tool lumbar switch parameters listed below change between Inactive and Forward/Rearward or UP/Down when pressing the appropriate lumbar switch.

* Driver Seat Lumbar Horizontal Switch

* Driver Seat Lumbar Vertical Switch

• If the parameter does not change
Refer to Circuit/System Testing - Lumbar Support Switch Circuit Test.

• If the parameter changes

4. Verify the lumbar motors listed below operate while operating the appropriate lumbar support switches in both directions.

* M53DL Seat Lumbar Support Motor - Driver Lower

* M53DU Seat Lumbar Support Motor - Driver Upper

• If either lumbar motor does not operate
Refer to Circuit/System Testing - Lumbar Support Motor Circuit Test.

• If both lumbar motors operate

5. All OK.

Circuit/System Testing

Lumbar Support Switch Circuit Test

1. Ignition OFF, disconnect the X2 harness connector at the S64D Driver Seat Adjuster Switch.

2. Verify the scan tool lumbar switch parameters listed below are Inactive:

* Driver Seat Lumbar Horizontal Switch

* Driver Seat Lumbar Vertical Switch

• If not Inactive

1. Ignition OFF, disconnect the X4 harness connector at the K40 Seat Memory Control Module.

2. Test for Infinite resistance between the appropriate signal circuit terminal listed below and ground.

* Lumbar up switch signal terminal 1

* Lumbar down switch signal terminal 5

* Lumbar forward switch signal terminal 2

* Lumbar rearward switch signal terminal 6

• 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

3. Install a 3 A fused jumper wire between each signal circuit terminal listed below and ground, one at a time.

* Lumbar up switch signal terminal 1

* Lumbar down switch signal terminal 5

* Lumbar forward switch signal terminal 2

* Lumbar rearward switch signal terminal 6

4. Verify the appropriate scan tool lumbar switch parameter is Froward/Rearward or Up/Down.

• If not Froward/Rearward or Up/Down

1. Ignition OFF, disconnect the X4 harness connector at the K40 Seat Memory Control Module, ignition ON.

2. 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

3. 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 Froward/Rearward or Up/Down

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

Lumbar Support Motor Circuit Test

1. Ignition OFF, disconnect the harness connector at the K104D Seat Lumbar Support Control Module - Driver.

2. Connect a DMM between each control circuit terminal listed below and ground one at a time, ignition ON.

* Lumbar up relay control terminal 2

* Lumbar down relay control terminal 6

* Lumbar forward relay control terminal 1

* Lumbar rearward relay control terminal 5

3. Test for B+ when commanding the Up/Down or Forward/Rearward states using the appropriate lumbar switch.

• If less than B+ during either of the commands

1. Ignition OFF, disconnect the X6 harness connector at the K40 Seat Memory Control Module.

2. 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

3. Test for less than 2 ohms in the 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 B+ during each of the commands

4. Ignition OFF, connect the harness connector at the K104D Seat Lumbar Support Control Module - Driver and disconnect the harness connector at the appropriate M53D Seat Lumbar Support Motor.

5. Connect a test lamp between control circuit terminal A and control circuit terminal B, ignition ON.

6. Verify the test lamp turns ON when commanding the Up/Down or Forward/Rearward states using the appropriate lumbar switch.

• If the test lamp remains OFF during either of the commands

1. Ignition OFF, disconnect the harness connector at the K104D Seat Lumbar Support Control Module - Driver.

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, test or replace the K104D Seat Lumbar Support Control Module - Driver.

• If the test lamp turns ON during each of the commands

7. Test or replace the M53D Seat Lumbar Support Motor.

Component Testing

Lumbar Support Switch

1. Ignition OFF, disconnect the X1 and X2 harness connector at the S64 Seat Adjuster Switch.

2. Test for infinite resistance between the ground terminal 6 X1 and each lumbar signal terminal with the switch in the open position.

• If less than infinite resistance
Replace the S64 Seat Adjuster Switch.

• If infinite resistance

3. Test for less than 2 ohms between the ground terminal 6 X1 and each lumbar signal terminal with the appropriate switch in the closed position.

• If 2 ohms or greater
Replace the S64 Seat Adjuster Switch.

• If less than 2 ohms

4. All OK.

Lumbar Support Motor

1. Ignition OFF, disconnect the harness connector at the appropriate M53D Seat Lumbar Support Motor.

Note: When performing the following tests, make sure that the lumbar support is not already in the position the test is attempting to produce.

2. Install a 30 A fused jumper wire between control terminal A and 12 V.

3. Momentarily install a jumper wire between control terminal B and ground. The lumbar motor should momentarily perform the appropriate FORWARD/ REARWARD function.

• If the motor does not perform the FORWARD/ REARWARD function
Replace the M53D Seat Lumbar Support Motor.

• If the motor performs the FORWARD/ REARWARD function

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

• If the motor does not perform the FORWARD/ REARWARD function
Replace the M53D Seat Lumbar Support Motor.

• If the motor performs the FORWARD/ REARWARD function

5. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Driver or Passenger Seat Adjuster and Recliner Switch Replacement Driver or Passenger Seat Adjuster and Recliner Switch Replacement

* Seat Lumbar Sub System Replacement Seat Lumbar Sub System Replacement

* Control Module References Control Module References for K40 Seat Memory Control Module replacement, programming and setup

pro multis Credits:Operation CHARM About Operation CHARM