Power Seat System Cadillac DTS I

Fastener Tightening Specifications

Scheme 40

Scheme 41

Scheme 42

Scheme 43

Scheme 44

Scheme 45

DIAGNOSTIC CODE INDEX

DIAGNOSTIC CODE INDEX

Diagnostic Starting Point - Seats

Begin the system diagnosis with the Diagnostic System Check - Vehicle . The Diagnostic System Check will provide the following information

1. The identification of the control modules which command the system.
2. The ability of the control modules to communicate through the serial data circuit.
3. The identification of any stored diagnostic trouble codes (DTCs) and their status.

The use of the Diagnostic System Check will identify the correct procedure for diagnosing the system and where the procedure is located.

Diagnostic Instructions

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit/System Description

The memory seat module (MSM) monitors the current supplied to the driver seat adjuster motors, recline motor and lumbar horizontal motor. It can detect both absolute and differential current levels from the seat motors. Absolute current is the maximum allowable current the module will supply to the motors. A differential current mismatch occurs when the current supplied to the seat motors does not match the current returning from the motors.

Conditions for Running the DTC

The driver seat adjuster motors, recline motor or the lumbar horizontal motor must be active.

B1335 00

The current out of the module does not match the current returning to the module from 1.5-5.0A.

B1335 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.

B1335 42

This DTC will set if the module calibration is not programmed.

B1335 4B

This DTC will set if the module calibration is out of range.

Action Taken When the DTC Sets

All movement related to the seat cushion and recline motors is aborted.

Conditions for Clearing the DTC

1. The current DTC will clear and set the code to history, 3 seconds after no motor movement is requested or the current is no longer mismatched, and the power mode changes to OFF then back to ACC or RUN.
2. The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

Diagnostic Aids

The scan tool may reference the Memory Seat Module (MSM) as the Driver Position Module.

Reference Information

Schematic Reference

1. «Driver Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Passenger Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)

Connector End View Reference

Component Connector End Views

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for Scan Tool Information

Circuit/System Testing

B1335 00 or B1335 0B

1. Use a scan tool to clear the current and history diagnostic trouble code.
2. Ignition ON, determine which motor set this DTC by operating the following motors one at a time in both directions. Check for the DTC to set between each motor test. Driver seat front vertical motor Driver seat rear vertical motor Driver seat horizontal motor Driver seat recline motor Driver seat lumbar horizontal motor
3. Use a scan tool to clear the current and history diagnostic trouble code.
4. Ignition OFF, disconnect the harness connector at the seat or lumbar motor for which the DTC set.
5. Ignition ON, operate the motor in both directions then verify that the DTC set. If the DTC did not set, test or replace the motor.
6. Ignition OFF, disconnect the appropriate X1 or X4 harness connector at the memory seat module.
7. Ignition ON, test for 0 volt between each motor control circuit and ground. If greater than 0 volt, test the control circuit for a short to voltage.
8. Test for infinite resistance between each control circuit and ground. If less than infinite resistance, test the control circuit for a short to ground.
9. Test for infinite resistance between the motor control circuits: If less than infinite resistance, test for a short between the control circuits.
10. If all circuits test normal, test or replace the memory seat module.

B1335 42 or B1335 4B

If either DTC is set history or current, the only option is module replacement.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Front Seat Adjuster Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Front Seat Recliner Actuator Motor Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
3. «Front Seat Lumbar Support Replacement (w/AM3)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) or «Front Seat Lumbar Support Replacement (w/AL2)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
4. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for MSM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The memory seat module (MSM) monitors the current supplied to driver and passenger seat lumbar vertical motors and both steering column actuators. The MSM can detect both absolute and differential current levels from the these motors. Absolute current is the maximum allowable current the module will supply to the motors. A differential current mismatch occurs when the current supplied to the motors does not match the current returning from the motors.

The seat lumbar motors or steering wheel actuators must be active.

B1340 0B

The absolute current has exceeded the maximum value allowed.

B1340 42

This DTC will set if the module calibration is not programmed.

B1340 4B

This DTC will set if the module calibration is not learned.

All movement related to the seat lumbar motors and steering wheel actuators is aborted.

1. The current DTC will clear and set the code to history, 3 seconds after no motor movement is requested or the current is no longer mismatched, and the power mode changes to OFF then back to ACC or RUN.
2. The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

The scan tool may reference the Memory Seat Module (MSM) as the Driver Position Module.

Schematic Reference

1. «Driver Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Passenger Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)

Connector End View Reference

Component Connector End Views

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for scan tool information

B1340 0B

1. Use a scan tool to clear the current and history diagnostic trouble code.
2. Ignition ON, determine which motor set this DTC by operating the motors listed below one at a time in both directions. Check for the DTC to set between each motor test. Driver Seat Lumbar Vertical Motor Passenger Seat Lumbar Vertical Motor Steering Column Tilt Actuator Steering Column Telescope Actuator
3. Use a scan tool to clear the current and history diagnostic trouble code.
4. Ignition OFF, disconnect the harness connector at the motor/actuator for which the DTC set.
5. Ignition ON, operate the motor/actuator in both directions then verify that the DTC set. If the DTC did not set, test or replace the motor/actuator.
6. Ignition OFF, disconnect the appropriate X1 or X4 harness connector at the memory seat module.
7. Ignition ON, test for 0 volts between the appropriate control circuit terminals listed below and ground. Driver Seat Lumbar Vertical Motor terminals 1 and 2 X4 Passenger Seat Lumbar Vertical Motor terminals 4 and 5 X4 Steering Column Tilt Actuator terminals 7 and 8 X4 Steering Column Telescope Actuator terminals 7 and 8 X1 If greater than the specified value, test the control circuit for a short to voltage.
8. Test for infinite resistance between each control circuit and ground. If not the specified value, test the control circuit for a short to ground.
9. Test for infinite resistance between the control circuits. If not the specified value, test for a short between the control circuits.
10. If all circuits test normal, test or replace the memory seat module.

B1340 42 or B1340 4B

If either DTC is set history or current, replace the MSM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Front Seat Lumbar Support Replacement (w/AM3)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) or «Front Seat Lumbar Support Replacement (w/AL2)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Tilt Motor Replacement»(/cadillac/dts/i-2005-2011/remont/steering-column-switches/#steering-wheel-steering-column)
3. «Telescope Actuator Assembly Replacement»(/cadillac/dts/i-2005-2011/remont/steering-column-switches/#steering-wheel-steering-column)
4. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for MSM replacement, programming and setup

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The memory seat module (MSM) supplies a 5-volt reference voltage to the driver seat position sensors, lumbar position sensors, passenger seat lumbar vertical position sensor, and the steering column position sensors. The MSM monitors this reference voltage to ensure the accuracy of the voltages being returned from the sensors. If the voltage exceeds the normal operating range, errors will occur in the memory recall operations of the seat and steering column.

The MSM must be powered.

B1395 02

The reference voltage drops below 4.8 volts for more than 300 mS.

B1395 05

The reference voltage exceeds 5.2 volts for more than 300 mS.

All memory recall and seat massage functions will be disabled.

1. The current DTC will clear and set the code to history 3 seconds after the reference voltage returns to normal operating range and the power mode changes to OFF then back to ACC or RUN.
2. The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

1. The scan tool may reference the Memory Seat Module (MSM) as the Driver Position Module.
2. All seat, lumbar, and tilt/telescoping steering column position sensors use common ground and 5-volt reference circuits.
3. If the 5-volt reference circuit is shorted to voltage multiple position sensor codes will set.
4. If the 5-volt reference circuit is shorted to ground multiple position sensor codes will set.
5. A short to voltage on one of the position sensor signal circuits may set this code.
6. An internal short to ground in one of the position sensors may set this code.

Schematic Reference

1. «Driver Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Passenger Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)

Connector End View Reference

Component Connector End Views

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for Scan Tool Information

1. Ignition OFF, disconnect the harness connector for all position sensors connected to the 5-volt reference circuit.
2. Ignition ON, observe all scan tool sensor parameters for Seat 1, Seat 2, and Column Info. The readings should be 0.0 volts. If greater than the specified value, test the appropriate signal circuit for a short to voltage. If the circuit tests normal, replace the MSM.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit at any one of the position sensors and ground. If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the MSM. If greater than 4.8 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the MSM.
4. Connect each position sensor associated with the 5 volt reference circuit one at a time while monitoring the measured voltage. The voltage reading should remain within the specified range. If not within the specified range, replace the position sensor.
5. If all circuits test normal, replace the MSM.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Front Seat Adjuster Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Front Seat Lumbar Support Replacement (w/AM3)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) or «Front Seat Lumbar Support Replacement (w/AL2)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
3. «Front Seat Recliner Position Sensor Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
4. «Tilt Motor Replacement»(/cadillac/dts/i-2005-2011/remont/steering-column-switches/#steering-wheel-steering-column)
5. «Telescope Actuator Assembly Replacement»(/cadillac/dts/i-2005-2011/remont/steering-column-switches/#steering-wheel-steering-column)
6. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for MSM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Circuit Description

When the power seat switches are pressed, they send a 12-volt signal through the switch signal circuits to the memory seat module (MSM). The MSM then commands the driver seat and lumbar motors to move in response to the switch signals.

The MSM must be powered.

Conditions for Setting the DTC

1. If a seat switch circuit is active in one direction and the switch for the opposite direction is pressed, this DTC will set.
2. A short to voltage on a switch signal circuit.

1. A motor output driven in response to a switch considered failed, is deactivated for both directions.
2. All memory recall commands are ignored.
3. The MSM will respond to any other switch signal that has not set a DTC.

1. The current DTC will clear and set the code to history, 3 seconds after the fault is no longer present and the power mode changes to OFF then back to ACC or RUN.
2. The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

1. The scan tool may reference the Memory Seat Module (MSM) as the Driver Position Module.
2. If one of the switch signal circuits is shorted to battery, multiple codes will set.

Schematic Reference

1. «Driver Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Passenger Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)

Connector End View Reference

Component Connector End Views

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for Scan Tool Information

Circuit/System Verification

Ignition ON, observe the scan tool Driver Position Module, Seat 1 Inputs seat switch parameters, while pressing the seat directional switches. The reading should change between Inactive and Active.

1. Ignition OFF, disconnect the harness connector at the appropriate seat or lumbar adjuster switch.
2. Ignition ON, verify the scan tool seat or lumbar switch parameters are Inactive. If not Inactive, test the signal circuit that displays Active for a short to voltage. If the circuit tests normal, replace the MSM.
3. If all circuits test normal, test or replace the appropriate seat or lumbar adjuster switch.

Component Testing

1. Ignition OFF, disconnect the harness connector at the appropriate seat or lumbar adjuster switch.
2. Test for infinite resistance between each seat direction signal terminal and the switch B+ terminal with the switch in the open position. If less than infinite resistance, replace the switch.
3. Test for less than 1 ohm of resistance between each seat direction signal terminal and the B+ terminal with the switch in the closed position. If greater than 1 ohm, replace the switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Power Seat Switch Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Rear Seat Lumbar Control Switch Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
3. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for memory seat module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The position sensor that sets this diagnostic trouble code (DTC) is either attached to the seat directional motor drive cable or directly to the motor it monitors. It receives a 5-volt reference and ground from the memory seat module (MSM). The sensor sends a voltage signal that varies with the movement of the seat through the signal circuit to the MSM. Then based on this voltage signal, the MSM determines the position of the seat.

The MSM must be powered.

B1825, B1850, B1860, B2105, B2355, B2365, B2375 01

If the MSM sees the analog input from this sensor is greater than 4.75 volts, the sensor will be considered out of range and the MSM will set this DTC.

B1825, B1850, B1860, B2105, B2355, B2365, B2375 06

If the MSM sees the analog input from this sensor is less than 0.22 volt, the sensor will be considered out of range and the MSM will set this DTC.

B1825, B1850, B1860, B2105, B2355, B2365, B2375 5A

This DTC will set, if the MSM is controlling a motor in one direction and it's position sensor is tracking the motor in the opposite direction. The sensor is either mounted or wired incorrectly, or the polarity of the motor control circuits are reversed.

All memory recall and seat massage functions will be disabled.

1. The current DTC will clear and set to history, when the MSM sees the analog input from the sensor as between 0.22 volt and 4.75 volts and the power mode changes to OFF then back to ACC or RUN.
2. The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

1. The scan tool may reference the Memory Seat Module (MSM) as the Driver Position Module.
2. All position sensors use common ground and 5-volt reference circuits.
3. If the 5-volt reference circuit is shorted to voltage multiple position sensor codes will set.
4. If the 5-volt reference circuit is shorted to ground multiple position sensor codes will set.
5. If the sensor ground circuit is open multiple codes will set.

Schematic Reference

1. «Driver Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Passenger Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)

Connector End View Reference

Component Connector End Views

Description and Operation

1. «Memory Seats Description and Operation»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system__memory-seats-description-operation)
2. «Lumbar Support Description and Operation (w/o Memory-A45)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) or «Lumbar Support Description and Operation (with Memory-A45)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) or «Lumbar Support Description and Operation (with Massaging Lumbar-AM3)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for Scan Tool Information

Ignition ON, observe the scan tool Driver Position Module, Driver Seat and Lumbar position sensor parameters. The readings should be between 0.22 volt and 4.75 volts and change while adjusting seat and lumbar positions.

B1825

1. Ignition OFF, disconnect the X2 harness connector at the driver seat recline motor.
2. Ignition OFF, test for less than 2 ohms of resistance between the low reference circuit terminal 3 and ground. If greater than 2 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the MSM.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 1 and ground. If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the MSM. If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the MSM.
4. Verify the scan tool Driver Seat Recline Sensor parameter is less than 2 volts. If greater than 2 volts, test the signal circuit terminal 2 for a short to voltage. If the circuit tests normal, replace the MSM.
5. Install a 3A fused jumper wire between the signal circuit terminal 2 and the 5-volt reference circuit terminal 1. Verify the scan tool Driver Seat Recline Sensor parameter is greater than 4.75 volts. If less than 4.75 volts, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the MSM.
6. If all circuits test normal, test or replace the seat recline position sensor.

B2355, B2365, B2375

1. Ignition OFF, disconnect the X2 harness connector at the driver seat adjuster motor assembly.
2. Ignition OFF, test for less than 2 ohms of resistance between the low reference circuit terminal 2 and ground. If greater than 2 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the MSM.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 6 and ground. If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the MSM. If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the MSM.
4. Verify the appropriate scan tool Driver Seat Sensor parameter is less than 2 volts. If greater than 2 volts, test the appropriate signal circuit for a short to voltage. If the circuit tests normal, replace the MSM. Seat front vertical position sensor terminal 1 Seat rear vertical position sensor terminal 5 Seat horizontal position sensor terminal 3
5. Install a 3A fused jumper wire between the signal circuit and the 5-volt reference circuit terminal 6. Verify the appropriate scan tool Driver Seat position sensor parameter is greater than 4.75 volts. Seat front vertical position sensor terminal 1 Seat rear vertical position sensor terminal 5 Seat horizontal position sensor terminal 3 If less than 4.75 volts, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the MSM.
6. If all circuits test normal, test or replace the seat adjuster motor assembly.

B1850, B1860, B2105

1. Ignition OFF, disconnect the X2 harness connector at the appropriate seat lumbar motor assembly.
2. Ignition OFF, test for less than 2 ohms of resistance between the low reference circuit terminal A and ground. If greater than 2 ohms, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the MSM.
3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal C and ground. If less than 4.8 volts, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the MSM. If greater than 5.2 volts, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the MSM.
4. Verify the appropriate scan tool Lumbar Sensor parameter is less than 2 volts. If greater than 2 volts, test the appropriate signal circuit for a short to voltage. If the circuit tests normal, replace the MSM. Lumbar vertical position sensor terminal B Lumbar horizontal position sensor terminal D
5. Install a 3A fused jumper wire between the signal circuit and the 5-volt reference circuit terminal C. Verify the appropriate scan tool Lumbar Sensor parameter is greater than 4.75 volts. Lumbar vertical position sensor terminal B Lumbar horizontal position sensor terminal D If less than 4.75 volts, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the MSM.
6. If all circuits test normal, test or replace the lumbar motor assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Front Seat Adjuster Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Front Seat Recliner Position Sensor Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
3. «Front Seat Lumbar Support Replacement (w/AM3)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) or «Front Seat Lumbar Support Replacement (w/AL2)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
4. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for memory seat module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

The memory seat module (MSM) controls the seat, recline, lumbar, and steering column motors via half bridges that are divided into 2 groups that are connected to separate power rails internal to the module.

1. Power rail 1 includes of the following motors: Seat front vertical motor Seat rear vertical motor Seat horizontal motor Seat recline motor Seat lumbar horizontal motor
2. Power rail 2 includes the following motors: Driver seat lumbar vertical motor Passenger seat lumbar vertical motor Steering column tilt actuator Steering column telescope actuator

The MSM connects all of the motor control circuits on each power rail to a common reference point whenever they are not in operation. This reference point is biased to approximately 2.5 volts. The MSM checks to see if this reference voltage is shorted to ground or battery before enabling any seat, lumbar, or steering column motor.

The scan tool may reference the Memory Seat Module (MSM) as the Driver Position Module.

B3920

All motor outputs for power rail 1 must be inactive for this DTC to set.

B3921

All motor outputs for power rail 2 must be inactive for this DTC to set.

B3920 01

The voltage on any power rail 1 motor control circuit exceeds 2.78 volts for 100 ms.

B3920 02

The voltage on any power rail 1 motor control circuit is below 1.47 volts for 100 ms.

B3921 01

The voltage on any power rail 2 motor control circuit exceeds 2.78 volts for 100 ms.

B3921 02

The voltage on any power rail 2 motor control circuit is below 1.47 volts for 100 ms.

The MSM will not allow operation of any motor on the power rail for which the DTC was set.

1. The current DTC clears and sets to history when the reference voltage is between 1.47 volts and 2.5 volts for 3 seconds and the power mode changes to OFF then back to ACC or RUN.
2. The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

Schematic Reference

1. «Driver Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Passenger Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)

Connector End View Reference

Component Connector End Views

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for Scan Tool Information

B3920 Group 1 Motors

1. Ignition OFF, disconnect the X1 harness connector at the memory seat module.
2. Ignition ON, verify that a test does not illuminate between any of the following motor control circuits and ground: Front vertical motor terminal 12 Front vertical motor terminal 13 Rear vertical motor terminal 15 Rear vertical motor terminal 16 Seat horizontal motor terminal 9 Seat horizontal motor terminal 10 If the test lamp illuminates, test the control circuit for a short to voltage.
3. Test for infinite resistance between the following motor control circuits and ground: Front vertical motor terminal 12 Front vertical motor terminal 13 Rear vertical motor terminal 15 Rear vertical motor terminal 16 Seat horizontal motor terminal 9 Seat horizontal motor terminal 10 If less than infinite resistance, test the motor control circuit for a short to ground.
4. Test for greater resistance values than specified between the following motor control circuits: 1 ohm for front vertical motor terminal 12 and terminal 13 1 ohm for rear vertical motor terminal 15 and terminal 16 1 ohm for seat horizontal motor terminal 9 and terminal 10 If less than the specified resistance, test the control circuits for a short together or shorted motor.
5. Ignition OFF, disconnect the X4 harness connector at the memory seat module.
6. Ignition ON, verify that a test does not illuminate between any of the following motor control circuits and ground: Lumbar horizontal motor terminal 12 Lumbar horizontal motor terminal 13 Seat recline motor terminal 15 Seat recline motor terminal 16 If the test lamp illuminates, test the control circuit for a short to voltage.
7. Test for infinite resistance between the following motor control circuits and ground: Lumbar horizontal motor terminal 12 Lumbar horizontal motor terminal 13 Seat recline motor terminal 15 Seat recline motor terminal 16 If less than infinite resistance, test the motor control circuit for a short to ground.
8. Test for greater resistance values than specified between the following motor control circuits: 10 ohms for lumbar horizontal motor terminal 12 and terminal 13 1 ohm for recline motor terminal 15 and terminal 16 If less than the specified resistance, test the control circuits for a short together or shorted motor.
9. If all circuits test normal, replace the memory seat module.

B3921 Group 2 Motors

1. Ignition OFF, disconnect the X4 harness connector at the memory seat module.
2. Ignition ON, verify that a test lamp does not illuminate between any of the following motor control circuits and ground: Driver seat lumbar vertical motor terminal 1 Driver seat lumbar vertical motor terminal 2 Passenger seat lumbar vertical motor terminal 4 Passenger seat lumbar vertical motor terminal 5 Steering column tilt actuator terminal 7 Steering column tilt actuator terminal 8 If the test lamp illuminates, test the control circuit for a short to voltage.
3. Test for infinite ohms of resistance between the following motor control circuits and ground: Driver seat lumbar vertical motor terminal 1 Driver seat lumbar vertical motor terminal 2 Passenger seat lumbar vertical motor terminal 4 Passenger seat lumbar vertical motor terminal 5 Steering column tilt actuator terminal 7 Steering column tilt actuator terminal 8 If less than infinite, test the control circuit for a short to ground.
4. Test for greater resistance values than specified between the following motor control circuits: 10 ohms for driver seat lumbar vertical motor terminal 1 and terminal 2 10 ohm for passenger seat lumbar vertical motor terminal 4 and terminal 5 1 ohm for steering column tilt actuator terminal 7 and terminal 8 If less than the specified resistance, test the control circuits for a short together or shorted motor.
5. Ignition OFF, disconnect the X1 harness connector at the memory seat module.
6. Ignition ON, verify that a test lamp does not illuminate between any of the following actuator control circuits and ground: Steering column telescope actuator terminal 8 Steering column telescope actuator terminal 7 If the test lamp illuminates, test the control circuit for a short to voltage.
7. Test for infinite ohms of resistance between the following actuator control circuits and ground: Steering column telescope actuator terminal 8 Steering column telescope actuator terminal 7 If less than infinite, test the control circuit for a short to ground.
8. Test for greater than 1 ohm of resistance between the steering column telescope actuator control circuits terminal 7 and terminal 8. If less than 1 ohm, test the control circuits for a short together or shorted actuator.
9. If all circuits test normal, replace the memory seat module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Front Seat Adjuster Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Front Seat Recliner Actuator Motor Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
3. «Front Seat Lumbar Support Replacement (w/AM3)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) or «Front Seat Lumbar Support Replacement (w/AL2)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
4. «Steering Column Replacement»(/cadillac/dts/i-2005-2011/remont/steering-column-switches/#steering-wheel-steering-column)
5. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for MSM replacement, programming and setup

Symptoms - Power Seats

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) before using the symptom tables 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. Refer to the system description and operation from the following list in order to familiarize yourself with the system functions: «Power Seats System Description and Operation»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system__power-seats-system-description-operation) «Lumbar Support Description and Operation (w/o Memory-A45)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) «Lumbar Support Description and Operation (with Memory-A45)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) «Lumbar Support Description and Operation (with Massaging Lumbar-AM3)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) «Memory Seats Description and Operation»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system__memory-seats-description-operation)

Visual/Physical Inspection

1. Inspect for aftermarket devices which could affect the operation of the power seats. Refer to «Checking Aftermarket Accessories»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__checking-aftermarket-accessories) .
2. Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.
3. Inspect the seat adjuster track for conditions which may cause binding or objects within the seat adjustment range which obstruct movement or interfere with wiring.

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

1. «Lumbar Massage Inoperative»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Lumbar Support Inoperative (w/o Memory A45)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) or «Lumbar Support Inoperative (w/ Memory A45)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
3. «Memory Seat Feature Inoperative»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
4. «Power Seat Inoperative (w/o Memory A45)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) or «Power Seat Inoperative (w/ Memory A45)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Battery positive voltage is supplied to the driver seat lumbar massage switch from the memory seat module (MSM) and to the passenger front seat from the MSM fuse. When the lumbar massage switch is pressed, battery voltage is applied through the switch contacts and the lumbar massage signal circuit to the MSM. The MSM then cycles battery voltage and ground through the lumbar vertical motor control circuits to the lumbar vertical motor for 10 minutes or until the massage function is canceled. The MSM supplies the lumbar vertical position sensor with a 5-volt reference and low reference circuits. When the motor rotates, the resistance of the potentiometer varies changing the voltage of the lumbar vertical position sensor signal to the MSM.

The MSM is referenced in the Tech 2 as the driver position module (DPM).

Connector End View Reference

Component Connector End Views

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for Scan Tool Information

Ignition ON, use a scan tool to observe the Massage Switch parameter while pressing the massage switch. The reading should change between Inactive and Active.

1. Using a scan tool verify the Massage Switch parameter is Inactive. If not Inactive, test the signal circuit for a short to voltage. If the circuit tests normal, replace the memory seat module.
2. Ignition OFF, disconnect the harness connector at the lumbar massage switch.
3. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal C and ground. If the test lamp does not illuminate, test the supply voltage for an open/high resistance.
4. Install a 3-amp fused jumper wire between the voltage supply circuit terminal C and the signal circuit terminal A. Verify the Massage Switch parameter is Active. If not Active, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the memory seat module.
5. If all circuits tests normal, replace the lumbar massage switch.

Lumbar Massage Switch

1. Ignition OFF, disconnect the harness connector at the lumbar massage switch.
2. Test for infinite resistance between the signal terminal and the supply voltage terminal with the switch in the open position. If less than infinite, replace the lumbar massage switch.
3. Test for less than 3 ohms between the signal terminal and the supply voltage terminal with the switch in the closed position. If greater than 3 ohms, replace the lumbar massage switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Front Seat Lumbar Control Switch Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system__front-seat-lumbar-control-switch-replacement)
2. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for MSM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Power seat lumbar support without memory is completely controlled through the seat lumbar adjuster switch. Battery voltage is supplied at all times to the front passenger seat lumbar adjuster switch from the MSM/RT FRT PWR SEAT 25A circuit breaker that is located in the rear fuse block. Battery voltage is supplied at all times to both rear passenger seat lumbar adjuster switches from the REAR SEAT LUM 20A fuse also located in the rear fuse block. When the seat adjuster switches are in an inactive state, the switch contacts are closed to the switch ground circuit.

Both lumbar motors are reversible. For example, when the lumbar horizontal forward switch is pressed to move the lumbar support forward, battery voltage is applied through the switch contacts and the lumbar motor forward control circuit to the motor. The motor is grounded through the lumbar motor rearward switch contacts and the lumbar motor rearward control circuit to the motor. The motor runs in order to drive the lumbar support forward toward the occupants back until the switch is released. Moving the lumbar support rearward works similarly to moving the lumbar support forward, except that battery positive voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction. The lumbar support vertical motor is also powered this way.

Schematic Reference

1. «Passenger Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Rear Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)

Connector End View Reference

Component Connector End Views

Description and Operation

Lumbar Support Description and Operation (w/o Memory-A45) or Lumbar Support Description and Operation (with Memory-A45) or Lumbar Support Description and Operation (with Massaging Lumbar-AM3)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for Scan Tool Information

1. Disconnect the harness connector at the lumbar adjuster switch.
2. Test for less than 1 ohm of resistance between the ground circuit terminal E and ground. If greater than 1 ohm, test the ground circuit for an open/high resistance.
3. Verify that a test lamp illuminates between the B+ circuit terminal G and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. Connect the harness connector at the lumbar adjuster switch.
5. Disconnect the harness connector at the lumbar motor assembly.
6. Connect a test lamp between the motor control circuit terminals for the inoperative motor.
7. Verify that the test lamp illuminates while pressing the lumbar switch in both directions. If the test lamp does not illuminate for both directions, test the motor circuits for a short to ground or an open/high resistance. If the circuits test normal replace the lumbar adjuster switch.
8. If the circuits test normal replace the lumbar motor assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Front Seat Lumbar Control Switch Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system__front-seat-lumbar-control-switch-replacement)
2. «Rear Seat Lumbar Control Switch Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
3. «Front Seat Lumbar Support Replacement (w/AM3)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) or «Front Seat Lumbar Support Replacement (w/AL2)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
4. «Rear Seat Lumbar Support Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

A low current battery voltage is supplied at all times to the memory seat module (MSM) from the 10A MSM LOGIC/RF MASSAGE fuse. This voltage is used by the MSM for logic power and to supply battery reference voltage to the seat and lumbar adjuster switches. Battery positive voltage is supplied at all times to the MSM from the MSM/LT FRT PWR SEAT 25A circuit breaker. This voltage is connected to power rail 1 internal to the MSM and is used to drive the driver seat adjuster motors, recline motor and the lumbar horizontal motor. Battery positive voltage is also supplied at all times to the MSM from the MSM/T&T 25A circuit breaker. This voltage is connected to power rail 2 and is used to drive the driver seat lumbar vertical motor, passenger seat lumbar vertical motor, and the tilt and telescoping steering column actuators. Each seat and lumbar adjuster motor is controlled by the MSM through 2 motor control circuits. The MSM connects all motor control circuits on each power rail to a common reference point whenever they are not in operation. This reference point is biased to approximately 2.5 volts. The MSM checks to see if the reference voltage is shorted to ground or battery before enabling any of the seat or lumbar motors.

All motors are reversible. For example, when the lumbar switch is operated to move the lumbar support forward, battery positive voltage is applied through the switch contacts and the lumbar horizontal forward switch signal circuit to the MSM. In response to this signal, the MSM applies battery voltage through the lumbar motor forward control circuit and ground through the lumbar motor rearward control circuit to the motor. The motor runs to drive the lumbar support forward toward the occupants back until the switch is released. Moving the lumbar support rearward works similarly to moving the lumbar support forward, except that battery positive voltage and ground are applied on the opposite circuits causing the motor to run in the opposite direction.

The scan tool may reference the Memory Seat Module (MSM) as the Driver Position Module.

Schematic Reference

1. «Driver Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Passenger Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)

Connector End View Reference

Component Connector End Views

Description and Operation

Lumbar Support Description and Operation (w/o Memory-A45) or Lumbar Support Description and Operation (with Memory-A45) or Lumbar Support Description and Operation (with Massaging Lumbar-AM3)

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for Scan Tool Information

1. Ignition ON, verify that none of the Driver Position Module Lumbar Switch parameters are Active while the switch is in an inactive state. If any of the switch parameters are Active, perform the «Switch Circuit Test»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) .
2. Observe the scan tool Driver Position Module Lumbar Switch parameters while pressing the related lumbar switch. The reading should change between Inactive and Active. If any of the Lumbar Switch parameters are not Active, perform the «Switch Circuit Test»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) .
3. If all lumbar switch inputs to the MSM function normal, preform the «Motor Control Circuit Test»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) .

Lumbar Adjuster Switch Circuit Test

1. Ignition OFF, disconnect the harness connector at the lumbar adjuster switch.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal G and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the memory seat module.
3. Verify that all scan tool Driver Position Module Lumbar Switch input parameters are Inactive. If not Inactive, test the appropriate signal circuit for a short to voltage. If the circuit tests normal, replace the memory seat module.
4. Install a 3A fused jumper wire between the inoperative switch signal circuit terminal and the B+ circuit terminal G. Verify the related scan tool Lumbar Switch parameter is Active. If not Active, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the memory seat module.
5. If all circuits test normal, test or replace the lumbar adjuster switch.

Motor Control Circuit Test

1. Disconnect the X3 harness connector at the memory seat module.
2. Verify that a test lamp illuminates between the B+ circuit terminal 2 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
3. Connect the X3 harness connector at the memory seat module.
4. Disconnect the X1 harness connector at the seat lumbar motor assembly.
5. Connect a test lamp between the motor control circuit terminals of the inoperative motor.
6. The test lamp should illuminate while pressing the switch in both directions. If the test lamp does not illuminate, test the motor control circuits for an open/high resistance. If the circuits test normal replace the memory seat module.
7. If all circuits test normal, test or replace the lumbar motor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Rear Seat Lumbar Control Switch Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Front Seat Lumbar Support Replacement (w/AM3)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) or «Front Seat Lumbar Support Replacement (w/AL2)»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
3. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for memory seat module replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Battery positive voltage is supplied to the memory function switch from the driver door module (DDM). When a memory switch is pressed, battery voltage is applied through the switch contacts, a series of resistors, and thorough the memory switch signal circuit to the DDM. The door control module then sends a message via the GMLAN serial data line to the memory seat module (MSM) indicating the memory recall request. The MSM then commands the appropriate seat motors to move to the pre-recorded seat positions stored in memory in response to the switch input.

1. The DDM is referenced in Tech 2 as the Driver Door Switch.
2. The MSM is referenced in the Tech 2 as the Driver Position Module.

Schematic Reference

Driver Seat Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for Scan Tool Information

1. Verify that all manual power seat and lumbar functions operate as described in the description and operation. Refer to «Memory Seats Description and Operation»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system__memory-seats-description-operation) .
2. Verify that the memory recall personalization option is ON. Refer to «Personalization Description and Operation»(/cadillac/dts/i-2005-2011/remont/memory-modules/#configurable-customer-control-system__personalization-description-operation) and «Vehicle Personalization»(/cadillac/dts/i-2005-2011/remont/memory-modules/#configurable-customer-control-system) .
3. Verify that memory positions for driver 1 and driver 2 have been recorded to memory, by observing the scan tool Driver Position Module, Memory Data 1 and Memory Data 2 parameters.

1. Ignition ON, verify the scan tool Driver Door Switch Memory Recall Switches parameter changes state while pressing the memory 1 switch. If the parameter does not change state, perform the Memory Switch component test. If the switch tests normal, replace the driver door module.
2. Verify the scan tool Memory Recall Switches parameter changes state while pressing the memory 2 switch. If the parameter does not change state, replace the memory switch.
3. Verify the scan tool Memory Recall Switches parameter changes state while pressing the EXIT switch. If the parameter does not change state, replace the memory switch.
4. If all circuits test normal, replace the memory seat module.

Memory Function Switch

1. Disconnect the X4 harness connector at driver door module.
2. Test for infinite resistance between the memory switch signal circuit terminal 5 and the switch supply voltage circuit terminal 14. If not infinite, replace the memory switch.
3. Test the resistance between terminals 14 and 5. Press the memory 1, memory 2, and EXIT buttons and compare the resistance readings to the values in the Memory Switch Values table below. If the resistance is not within the specified range, replace the memory switch.

Memory Switch Values

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Driver Seat Adjuster Memory Switch Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for MSM and DDM replacement, setup, and programming

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

Power seat without memory is completely controlled through the seat adjuster switch. Battery voltage is supplied at all times to the seat adjuster switch from the memory seat module MSM/RT FRT PWR SEAT 25A circuit breaker that is located in the rear fuse block. When the seat adjuster 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 forward control circuit to the motor. The motor is grounded through the horizontal motor rearward switch contacts and the horizontal motor rearward control circuit to the motor. 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.

Schematic Reference

1. «Driver Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Passenger Seat Schematics»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)

Connector End View Reference

Component Connector End Views

Description and Operation

Power Seats System Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for Scan Tool Information

1. Disconnect the harness connector at the seat adjuster switch.
2. Test for less than 1 ohm of resistance between the ground circuit terminal B and ground. If greater than 1 ohm, test the ground circuit for an open/high resistance.
3. Verify that a test lamp illuminates between the B+ circuit terminal and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
4. Connect the harness connector at the seat adjuster switch.
5. Disconnect the harness connector at the appropriate seat motor assembly.
6. Connect a test lamp between the motor control circuit terminals for the inoperative motor.
7. Verify that the test lamp illuminates while pressing the appropriate seat switch in both directions. If the test lamp does not illuminate for both directions, test the motor circuits for a short to ground or an open/high resistance. If the circuits test normal replace the seat adjuster switch.
8. If the circuits test normal replace the inoperative motor assembly.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Power Seat Switch Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Front Seat Adjuster Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
3. «Front Seat Recliner Actuator Motor Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)

1. Perform the «Diagnostic System Check - Vehicle»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-system-check-vehicle) prior to using this diagnostic procedure.
2. Review «Strategy Based Diagnosis»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__strategy-based-diagnosis) for an overview of the diagnostic approach.
3. «Diagnostic Procedure Instructions»(/cadillac/dts/i-2005-2011/remont/oem-general-information/#vehicle-diagnostic-information__diagnostic-procedure-instructions) provides an overview of each diagnostic category.

A low current battery voltage is supplied at all times to the memory seat module (MSM) from the 10A MSM LOGIC/RF MASSAGE fuse. This voltage is used by the MSM for logic power and to supply battery reference voltage to the seat and lumbar adjuster switches. Battery positive voltage is supplied at all times to the MSM from the MSM/LT FRT PWR SEAT 25A circuit breaker. This voltage is connected to power rail 1 internal to the MSM and is used to drive the driver seat adjuster motors, recline motor and the lumbar horizontal motor. Battery positive voltage is also supplied at all times to the MSM from the MSM/T&T 25A circuit breaker. This voltage is connected to power rail 2 and is used to drive the driver seat lumbar vertical motor, passenger seat lumbar vertical motor, and the tilt and telescoping steering column actuators. Each seat and lumbar adjuster motor is controlled by the MSM through 2 motor control circuits. The MSM connects all motor control circuits on each power rail to a common reference point whenever they are not in operation. This reference point is biased to approximately 2.5 volts. The MSM checks to see if the reference voltage is shorted to ground or battery before enabling any of the seat or lumbar motors.

All motors are reversible. For example, when the seat switch is operated to move the entire seat forward, battery positive voltage is applied through the switch contacts and the power seat horizontal forward switch signal circuit to the MSM. In response to this signal, the MSM 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.

The scan tool may reference the Memory Seat Module (MSM) as the Driver Position Module.

Schematic Reference

Driver Seat Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

1. «Circuit Testing»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__circuit-testing)
2. «Connector Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__connector-repairs)
3. «Testing for Intermittent Conditions and Poor Connections»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__testing-for-intermittent-conditions-poor)
4. «Wiring Repairs»(/cadillac/dts/i-2005-2011/remont/ignition-switchsteering-lock/#wiring-systems-and-power-management-service-troubleshooting-diagnosis__wiring-repairs)

Scan Tool Reference

Control Module References for Scan Tool Information

1. Ignition ON, observe the scan tool Driver Position Module seat switch parameters. Verify that none of the seat switch parameters are Active while in an inactive state. If any of the switch parameters are Active, perform the «Switch Circuit Test»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) .
2. Observe the scan tool seat switch parameters while pressing and releasing the related seat switch. The reading should change between Inactive and Active. If any of the switch parameters are not Active, perform the «Switch Circuit Test»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) .
3. If all switch inputs to the MSM function normal, preform the «Motor Control Circuit Test»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system) .

Seat Adjuster Switch Circuit Test

1. Ignition OFF, disconnect the harness connector at the seat adjuster switch.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal E and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the memory seat module.
3. Install a 3A fused jumper wire between the inoperative switch signal circuit terminal and the B+ circuit terminal E. Verify the related scan tool Driver Position Module Seat Switch parameter is Active. If not Active, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the memory seat module.
4. If all circuits test normal, test or replace the seat adjuster switch.

Motor Control Circuit Test

1. Disconnect the X3 harness connector at the memory seat module.
2. Verify that a test lamp illuminates between the B+ circuit terminal 5 and ground. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
3. Connect the X3 harness connector at the memory seat module.
4. Disconnect the X1 harness connector at the appropriate seat adjuster motor assembly or seat recline motor.
5. Connect a test lamp between the motor control circuit terminals of the inoperative motor.
6. Verify that a test lamp illuminates while pressing the seat switch in both directions. If the test lamp does not illuminate, test the motor control circuits for an open/high resistance. If the circuits test normal replace the memory seat module.
7. If all circuits test normal, test or replace the inoperative seat motor.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

1. «Power Seat Switch Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
2. «Front Seat Adjuster Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
3. «Front Seat Recliner Actuator Motor Replacement»(/cadillac/dts/i-2005-2011/remont/seats/#power-seat-system)
4. «Control Module References»(/cadillac/dts/i-2005-2011/remont/communication-devices/#programming-and-setup-all-systems__control-module-references) for memory seat module replacement, setup, and programming

Scheme 46

Scheme 47

Scheme 48

Scheme 49

Front Seat Lumbar Control Switch Replacement

Scheme 50

Scheme 51

Scheme 52

Scheme 53

Scheme 54

Scheme 55

Lumbar Support Components

The front and rear passenger seat lumbar support systems consist of the following components

1. Lumbar switch
2. Lumbar horizontal motor
3. Lumbar vertical motor
4. MSM/RT FRT PWR SEAT Circuit Breaker 25 A
5. RR SEAT LUM fuse 20 A

Lumbar Switch

The lumbar switch provides both power and ground to the selected lumbar motors. Battery positive voltage is supplied at all times to the front passenger seat lumbar switch from the MSM/RT FRT PWR SEAT Circuit Breaker located in the rear fuse block. Battery positive voltage is supplied to both rear seat lumbar switch from the RR SEAT LUM fuse also located in the rear fuse block. Ground for the front and rear lumbar switches is supplied from the following ground stakes

1. G300 for the front passenger lumbar switch
2. G301 for the left rear passenger lumbar switch
3. G304 for the right rear passenger lumbar switch

Motors

The lumbar support system consists of two lumbar motors, horizontal and vertical, that operate independently of each other. Each motor contains an electronic circuit breaker (PTC) that will reset only after voltage has been removed from the motor. The lumbar horizontal motor moves the lumbar support forward and rearward and the lumbar vertical motor moves the lumbar support up and down.

Horizontal

When the lumbar switch is operated to move the lumbar support rearward, battery positive voltage is applied through the lumbar rearward switch contacts and the lumbar motor rearward control circuit to the lumbar horizontal motor. The motor is grounded through the lumbar forward switch contacts and the lumbar motor forward control circuit to the horizontal motor. The motor runs to drive the lumbar support rearward away from the occupant's back until the switch is released. Moving the lumbar support forward works similarly to moving the lumbar support rearward, except that battery positive voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction.

Vertical

When the lumbar switch is operated to move the lumbar support up, battery positive voltage is applied through the lumbar up switch contacts and the lumbar motor up control circuit to the lumbar vertical motor. The motor is grounded through the lumbar down switch contacts and the lumbar motor down control circuit to the vertical motor. The motor runs to drive the lumbar support up until the switch is released. Moving the lumbar support down works similarly to moving the lumbar support up, except that battery positive voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction.

The driver seat lumbar support system with memory (A45) consists of the following components

1. Lumbar switch
2. Memory seat module (MSM)
3. Lumbar horizontal motor
4. Lumbar vertical motor
5. Lumbar horizontal position sensor
6. Lumbar vertical position sensor
7. MSM LOGIC/RF MASSAGE Fuse 10 A

The MSM is referenced in the Tech 2 as the driver position module (DPM).

Battery positive voltage is supplied at all times to the driver and front passenger seat lumbar switches from the MSM LOGIC/RF MASSAGE Fuse located in the rear fuse block. When the lumbar switches are pressed they send a 12-volt signal to the memory seat module (MSM). The MSM then commands the lumbar motors to move in response to the switch signals.

The lumbar support system consists of 2 motors, horizontal and vertical, that operate independently of each other. The lumbar horizontal motor moves the lumbar support in the forward or rearward directions while the lumbar vertical motor moves the lumbar support in the up or down directions. Each motor contains an electronic circuit breaker (PTC) that opens in the event of a circuit overload and will reset only after voltage has been removed from the circuit.

Soft stop functions are not used for driver seat motors that are controlled by either a memory or non-memory MSM. However, soft stop functions are used for the MSM controlled steering column motors. Refer to Steering Wheel and Column Description and Operation .

Lumbar Horizontal Movement

When the lumbar switch is operated to move the lumbar support forward, battery positive voltage is applied through the switch contacts and the driver seat lumbar forward switch signal circuit to the memory seat module (MSM). In response to this signal, the MSM applies battery positive voltage through the lumbar motor forward control circuit and ground through the lumbar motor rearward control circuit to the motor. The motor runs to drive the lumbar support forward toward the occupant's back until the switch is released. Moving the lumbar support rearward works similarly to moving the lumbar support forward, except that battery positive voltage and ground are applied on the opposite circuits causing the motor to run in the opposite direction. The MSM also controls the lumbar horizontal motor during memory recall functions.

For front passenger lumbar horizontal movement refer to Lumbar Support Description and Operation without memory-A45 .

Lumbar Vertical Movement

When the lumbar switch is operated to move the lumbar support up, battery positive voltage is applied through the switch contacts and the lumbar up switch signal circuit to the memory seat module (MSM). In response to this signal, the MSM applies battery positive voltage through the lumbar motor up control circuit and ground through the lumbar motor down control circuit to the motor. The motor runs to drive the lumbar support up until the switch is released. Moving the lumbar support down works similarly to moving the lumbar support up, except that battery positive voltage and ground are applied on the opposite circuits causing the motor to run in the opposite direction. The MSM also controls the lumbar vertical motor during memory recall functions.

Lumbar Position Sensors

The lumbar position sensors are potentiometers which are an internal part of each lumbar motor. The memory seat module (MSM) supplies a 5-volt reference voltage through the 5-volt reference circuit and ground through the low reference circuit to each lumbar position sensor. When the lumbar motor rotates, the resistance of the potentiometer varies changing the feedback voltage of the position sensor signal circuit. This voltage varies from 0.27-4.65 volts. The MSM monitors this voltage signal to determine the lumbar position.

When a memory set command is received, the MSM records the lumbar position by storing the feedback voltage from each position sensor. Then when a memory recall command is received, the MSM moves the motors until the position sensor feedback voltages equals the feedback voltages stored in memory. The lumbar support is not involved in the easy exit function and the front passenger lumbar vertical support is not involved in memory recall functions.

Memory Functions

Refer to Memory Seats Description and Operation .

Lumbar Massage Components

The massaging lumbar system consists of the following components

1. Lumbar Switch
2. Memory seat module
3. Lumbar vertical motor
4. Lumbar vertical position sensor

Massage Operation

With the ignition in the ON position, battery positive voltage is supplied to the driver and front passenger lumbar massage switches from the memory seat module (MSM). When the switch is momentarily pressed to initiate massage operation, battery voltage is applied through the switch contacts and the lumbar massage switch signal circuit to the MSM. In response to this signal, the MSM then cycles battery positive voltage and ground through the lumbar motor up and down control circuits to the lumbar vertical motor. The motor will then continuously move the lumbar support 50 mm in both the up and down directions for 10 minutes or until the lumbar switch is momentarily pressed to cancel the operation. When massage operation has ceased, the MSM will return the lumbar support to the position from which massage was initiated.

During massage operation, the lumbar horizontal support can be adjusted without interruptions to the massage cycle by operating the lumbar switch in either the forward or rearward directions. However, manually moving the lumbar vertical switch in either the up or down directions will cancel the massage operation and move the lumbar support in the desired direction.

Lumbar Vertical Motor

The lumbar vertical motor is reversible. When commanded, it will move the lumbar support in the up and down directions. To protect itself, the motor contains an electronic circuit breaker (PTC) that opens in the event of a circuit overload and will reset only after voltage has been removed from the circuit. The lumbar vertical motor is controlled by the memory seat module during manual movement and massage operation.

Position Sensor

The lumbar vertical position sensor is a potentiometer, which is attached directly to the lumbar vertical motor. The memory seat module (MSM) supplies a 5 volt reference voltage through the 5 volt reference circuit and ground through the low reference circuit to the sensor. When the motor rotates, the resistance of the potentiometer varies, changing the feed back voltage of the sensor signal to the MSM. This voltage varies from 0.25 volts to 4.75 volts. The MSM monitors this voltage to determine the vertical position of the lumbar support. When the massage function is turned OFF or canceled, the MSM will stop massage movement at the original starting position.

Memory Seats Description & Operation

The Memory Seat System consists of the following components

1. Memory seat module (MSM)
2. Seat horizontal motor
3. Seat front vertical motor
4. Seat rear vertical motor
5. Seat recline motor
6. Lumbar horizontal motor
7. Lumbar vertical motor
8. Seat horizontal position sensor
9. Seat front vertical position sensor
10. Seat rear vertical position sensor
11. Seat recline position sensor
12. Lumbar horizontal positional sensor
13. Lumbar vertical position sensor
14. Seat adjuster switch
15. Seat lumbar switch
16. Memory function switch
17. MSM/LT FRT PWR SEAT Circuit Breaker 25 A
18. MSM/TILT STR WHL (DTS) Circuit Breaker 25 A
19. MEM LOGIC/RF MASSAGE Fuse 10 A

The MSM is referenced in the Tech 2 as the driver position module (DPM).

Memory Recall Option

The memory seat module (MSM) cannot perform memory recall functions unless the Memory Recall Option is activated. The memory recall option is located in the driver information center (DIC). The DIC reports the memory recall option setting to the MSM, as well as other receiving modules, via GMLAN message each time the ignition switch is cycled to the ON position. The MSM will then store the memory recall option setting and examine it before making a memory seat adjustment. The memory recall option setting stored within the MSM will not change until the memory recall option setting in the DIC is changed and the ignition switch is cycled to the ON position. The Easy Exit Option is also programmed this way, refer to Driver Information Center (DIC) Description and Operation .

Power Seat Switches

Battery positive voltage is supplied at all times to the seat adjuster switch from the memory seat module (MSM) and the MEM Logic/RF MASSAGE Fuse located in the rear fuse block. When the seat switches are pressed they send a 12-volt signal to the MSM. The MSM commands the selected seat motor to move in response to the switch inputs.

MSM Power & Grounds

Battery positive voltage is supplied at all times to the memory seat module (MSM) from the following circuit breakers and fuse located in the rear fuse block

1. MSM/LT FRT PWR SEAT Circuit Breaker: This voltage is used by the MSM to apply power to the driver seat and lumbar motors when commanded.
2. MSM/TILT STR WHL (DTS) Circuit Breaker: This voltage is used by the MSM to apply power to the steering column motors and the front passenger seat lumbar vertical motor when commanded.
3. MSM LOGIC/RF MASSAGE Fuse: This voltage is used to power up MSM.

Seat Motors

The memory seat module (MSM) controls the movement of each of the above mentioned seat directional motors, lumbar motors and the passenger seat lumbar vertical motor. Refer to Lumbar Support Description and Operation (w/o Memory-A45) or Lumbar Support Description and Operation (with Memory-A45) or Lumbar Support Description and Operation (with Massaging Lumbar-AM3) . All of the motors operate independently of each other. Each motor contains a electronic circuit breaker (PTC), which will reset only after voltage has been removed from the motor.

There are 4 motors that move the position of the seat. These are the seat horizontal motor, front vertical motor, rear vertical motor and the recline motor. The horizontal motor moves the entire seat forward and rearward. Both vertical motors run simultaneously when the seat switch is operated in order to move the entire seat up and down. Or they can be selected independently to vertically tilt the front or rear of the seat up and down. The recline motor moves the angle of the seat back forward or rearward.

All seat motors are reversible. For example, when a seat switch is pressed to move the entire seat forward, battery positive voltage is applied through the power seat horizontal forward switch signal circuit to the MSM. In response to this signal, the MSM applies battery positive 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 in order to drive the entire seat forward. 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 of the seat motors are powered this way.

Soft stop functions are not used for driver seat motors that are controlled by either a memory or non-memory MSM. However, soft stop functions are used for the MSM controlled steering column motors. Refer to Steering Wheel and Column Description and Operation .

Position Sensors

The seat position sensors are potentiometers which are either attached directly to the motor transmission cable or are an internal part of the motor. The memory seat module (MSM) supplies a 5-volt reference through the 5-volt reference circuit and ground through the sensor low reference circuit to the respective seat position sensors. When the motor or cable rotates, the resistance of the potentiometer varies changing the feedback voltage of the position sensor signal circuit. The voltage varies from 0.22-4.75 volts. The MSM monitors this voltage signal to determine the position of the seat. When a memory set command is received, the MSM records the seat position by storing the feedback voltage from each position sensor. When a memory recall command is received, the MSM moves the motors until the position sensor feedback voltages equals the feedback voltages stored in memory. For the easy exit function, only seat position sensor feedback voltages are recorded and only the seat motors are controlled. The lumbar support is not involved in the easy exit function.

Battery voltage is supplied at all times to the memory function switch from the driver door module that is located on the driver door panel. When a memory switch is pressed, a reduced voltage from a series of resistors is applied through the switch contacts and the memory recall switch signal circuit to the driver door module (DDM). In response to the memory request, the DDM then sends a message to the memory seat module (MSM) via GMLAN serial data line indicating the memory request.

The current seat position may be recorded for 2 different drivers. To record a position, adjust the drivers seat, lumbar support, steering wheel, and both outside mirrors to a comfortable position. Then press and hold the memory 1 button until two beeps sound through the driver's side front speaker. A second seating and mirror position may be programmed by repeating the above steps and pressing button 2, for driver 2. When the MSM receives a memory set message, the MSM records the feedback voltages from the seat recline, and lumbar position sensors for the appropriate driver. Two personalized exit positions can be set by first recalling driver position 1 or 2, positioning the seat and steering wheel, except the lumbar support, in the desired exit positions and then press and hold the memory exit button until two beeps sound. When the MSM receives a set easy exit message, it records the feedback voltages from the seat position sensors and the for the appropriate driver.

When the a memory recall button is pressed, a single chime is sounded through the driver's side front speaker in order to acknowledge the signal has been received, while the MSM receives the memory recall message. The MSM then applies battery positive voltage to the appropriate motors until the position sensor feedback voltages equal the feedback voltages stored in memory for the identified driver. When the EXIT button is pressed, a single chime is sounded in order to acknowledge the signal and the MSM receives the easy exit message. The MSM then applies battery positive voltage to the seat motors until the position sensor feedback voltages equal the feedback voltages stored in memory for the identified driver exit position.

Memory recall will not work if the shift lever is out of NEUTRAL (N) or PARK (P).

Recall Personalization

Refer to Driver Information Center (DIC) Description and Operation and Personalization Description and Operation for the following memory personalization options

1. Recall upon receipt of the RKE message
2. Recall upon receipt of the remote start feature
3. Easy exit
4. Factory settings

Memory Inhibit/Enable

The memory seat module (MSM) receives the ignition switch signal and the gear selector position via GMLAN messages. When the ignition switch is in the OFF position, memory record, memory recall, personalization recall, and exit recall functions are all allowed. When the ignition switch is in the ON position and the gear selector is in the PARK position, only the recall personalization function is deactivated and all other memory functions are allowed. When the ignition switch is in the ON position and the gear selector is out of the PARK position, only memory record is allowed, all other memory seat functions are not allowed.

Power Seats System Description & Operation

The driver and front passenger power seat systems each consist of the following components

1. Seat Adjuster Switch
2. Seat Horizontal Motor
3. Seat Front Vertical Motor
4. Seat Rear Vertical Motor
5. Seat Recline Motor
6. MSM/LT FRT PWR SEAT Circuit Breaker 25 A
7. MSM/RT FRT PWR SEAT Circuit Breaker 25 A

Seat Adjuster Switch

Battery positive voltage is supplied at all times to the driver and front passenger seat adjuster switches from their respective Circuit Breakers that are located in the rear fuse block. Both seat adjuster switches are grounded through the switch ground circuit and G 300. The seat adjuster switches provide both power and ground to the selected seat motors.

All of the seat motors operate independently of each other. Each motor contains an electronic circuit breaker (PTC) that will reset only after voltage has been removed from the motor. There are four seat position motors. These are the horizontal motor, front vertical motor, rear vertical motor, and the seat back recline motor. The horizontal motor moves the entire seat forward and rearward. Both vertical motors run simultaneously when the seat switch is operated to move the entire seat up and down. Or they can be selected independently to vertically tilt the front or rear of the seat up and down. The recline motor moves the angle seat back forward and rearward.

When the seat switch is operated to move the entire seat forward, battery positive voltage is applied through the horizontal motor forward switch contacts and the horizontal motor forward control circuit to the motor. The motor is grounded through the horizontal motor rearward switch contacts and the horizontal motor rearward control circuit to the motor. 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.

Rear Vertical

When the seat switch is operated to tilt the rear of the seat up, battery positive voltage is applied through the rear vertical motor up switch contacts and the rear vertical motor up control circuit to the rear vertical motor. The motor is grounded through the rear vertical motor down switch contacts and the rear vertical motor down control circuit to the rear vertical motor. The motor runs in order to drive the rear of the seat up until the switch is released. Tilting the rear of the seat down works similarly to tilting the rear of the seat up, except that battery positive voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction.

Front Vertical

When the seat switch is operated to tilt the front of the seat up, battery positive voltage is applied through the front vertical motor up switch contacts and the front vertical motor up control circuit to the front vertical motor. The motor is grounded through the front vertical motor down switch contacts and the front vertical motor down control circuit to the front vertical motor. The motor runs in order to drive the front of the seat up until the switch is released. Tilting the front of the seat down works similarly to tilting the front of the seat up, except that battery positive voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction.

Entire Seat Up or Down

When the seat switch is operated in order to move the entire seat to the up position, battery positive voltage is simultaneously applied through the front and rear vertical motor up switch contacts and the front and rear vertical motor up control circuits to both vertical motors. The motors are grounded through the front and rear vertical motor down switch contacts and the front and rear vertical motor down control circuits to both vertical motors. Both motors run simultaneously in order to drive the entire seat up until the switch is released. Moving the entire seat down works similarly to moving the entire seat up, except that battery positive voltage and ground are applied on the opposite circuits causing the motors to run in the opposite direction.

Recline

When the seat recline switch is operated to move the seat back forward, battery positive voltage is applied through the recline motor forward switch contacts and the recline motor forward control circuit to the recline motor. The motor is grounded through the recline motor rearward switch contacts and the recline motor rearward control circuit to the recline motor. The motor runs in order to move the seat back forward until the switch is released. Moving the seat back rearward works similarly to moving the seat back forward, except that battery positive voltage and ground are applied on the opposite circuits causing the motor to run in the opposite direction.

See also:
• Diagnostic System Check - Vehicle
• Strategy Based Diagnosis
• Diagnostic Procedure Instructions
• Component Connector End Views
• Circuit Testing
• Connector Repairs
• Testing for Intermittent Conditions and Poor Connections
• Wiring Repairs
• Control Module References
• Diagnostic Repair Verification
• Tilt Motor Replacement
• Checking Aftermarket Accessories
• Personalization Description and Operation
• Vehicle Personalization
• Front Seat Cushion Outer Trim Panel Replacement
• Front Side Door Trim Panel Replacement
• Fastener Notice
• SIR Disabling and Enabling
• Fastener Tightening Specifications
• Inflatable Restraint Side Impact Module Replacement - Front
• Driver Information Center (DIC) Description and Operation
• DTC B1335
• Memory Seats Description and Operation
• Power Seats System Description and Operation
• Front Seat Lumbar Control Switch Replacement
• Fastener Tightening Specifications