Buick Encore: Power Seats - Diagnostic information and procedures

DTC B1735, B1740, B1745, B1750, B1755, B1760, B1815, OR B1820: Driver seat switch

DIAGNOSTIC CODE INDEX

Diagnostic Instructions

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

DTC Descriptors

DTC B1735 02

Driver Seat Front Up Switch Circuit Short to Ground

DTC B1740 02

Driver Seat Front Down Switch Circuit Short to Ground

DTC B1745 02

Driver Seat Rear Up Switch Circuit Short to Ground

DTC B1750 02

Driver Seat Rear Down Switch Circuit Short to Ground

DTC B1755 02

Driver Seat Assembly Forward Switch Circuit Short to Ground

DTC B1760 02

Driver Seat Assembly Rearward Switch Circuit Short to Ground

Diagnostic Fault Information

Circuit/System Description

The seat memory control module supplies a reference voltage to each signal circuit of the driver seat adjuster switch. When the power seat switches are pressed, the appropriate signal circuit from the seat memory control module is pulled low through the switch contacts indicating the power seat command. The seat memory control module then commands the driver seat to move in response to the switch signals.

Conditions for Running the DTC

• DTC B1325 must not be present.
• Module battery voltage must be between 9-16 V.

Conditions for Setting the DTC

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

Action Taken When the DTC Sets

• A motor output driven in response to a switch considered failed, is deactivated for both directions.

  All memory recall commands are ignored.

• The seat memory control module will respond to any other switch signal that has not set a DTC.

Conditions for Clearing the DTC

• The current DTC will clear and set the code to history, when the fault is no longer present and the ignition is cycled OFF then back to ACC or RUN.
• The history DTC will clear after 40 consecutive fault-free ignition cycles have occurred.

Diagnostic Aids

• If one of the switch signal circuits is shorted to ground, multiple codes will set.
• If a switch is stuck in one direction and the switch is pressed in the opposite direction, a single code will set.

Reference Information

Schematic Reference

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

Connector End View Reference

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

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.
2. Verify the scan tool seat switch parameters listed below change between Inactive and Forward/Rearward or UP/Down when pressing the appropriate seat directional switch.

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

If the parameter does not change

Refer to Circuit/System Testing.

If the parameter changes

3. All OK.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the S64D Seat Adjuster Switch - Driver, Ignition ON.
2. Verify that all scan tool driver seat switch parameters listed below are Inactive:

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

If not Inactive

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

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

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

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

If Inactive

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

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

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

If not Forward/Rearward or UP/Down

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

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

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

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

If Forward/Rearward or UP/Down

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

Component Testing

Seat Adjuster Switch Test

1. Ignition OFF, disconnect the harness connector at the Seat Adjuster Switch - Driver.
2. Test for infinite resistance between the ground terminal D and each signal terminal with the switch in the open position.

If less than infinite resistance

Replace the Seat Adjuster Switch - Driver.

If infinite resistance

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

If 2 ohms or greater

Replace the Seat Adjuster Switch - Driver.

If less than 2 ohms

4. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

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

DTC B1825, B2355, B2365, OR B2375: Driver seat front vertical position sensor

Diagnostic Instructions

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

DTC Descriptors

DTC B2355 01

Driver Seat Front Vertical Position Sensor Circuit Short to Battery

DTC B2355 06

Driver Seat Front Vertical Position Sensor Circuit Low Voltage/Open

DTC B2365 01

Driver Seat Rear Vertical Position Sensor Circuit Short to Battery

DTC B2365 06

Driver Seat Rear Vertical Position Sensor Circuit Low Voltage/Open

DTC B2375 01

Driver Seat Assembly Horizontal Position Sensor Circuit Short to Battery

DTC B2375 06

Driver Seat Assembly Horizontal Position Sensor Circuit Low Voltage/Open

Diagnostic Fault Information

Circuit Description

The seat memory control module monitors the position of the seat motors by using hall effect position sensors which are an internal part of each motor. The module supplies each sensor with a 12 V reference circuit and a low side signal circuit. During seat motor operation, the hall effect position sensor provides a determined number of pulse signals for every revolution of the motor shaft. The scan tool displays these pulse signals as counts that range from 0-65,535. The module counts the feedback pulses from each sensor to determine seat position and end of travel limits for each of the seat motors. High scan tool count values indicate forward or upward seat positions while low count values indicate rearward or downward seat positions.

Conditions for Running the DTC

• DTC B1325 must not be present.
• Module battery voltage must be between 9-16 V.

Conditions for Setting the DTC

The seat memory control module does not detect position sensor movement or pulse signals while the adjuster motor is active. The following conditions will set this DTC:

B2355 01, B2365 01, or B2375 01

The seat memory control module detects a voltage greater than 5 V on the sensor signal circuit.

B2355 06, B2365 06, or B2375 06

The seat memory control module detects a short to ground or an open on the sensor signal circuit.

Action Taken When the DTC Sets

• With a short to ground or an open circuit, the seat memory control module disables the memory recall and easy exit/entry action commands of the motor monitored by the sensor. The motor will respond to manual position commands.
• With a short to battery voltage, the seat memory control module disables the memory recall and easy exit/entry action commands for all four seat motors. The motors will respond to manual position commands.

Conditions for Clearing the DTC

• The current DTC clears when the fault is no longer present and the power mode changes to OFF then back to ACC or RUN.
• The history DTC will clear after 40 consecutive fault-free ignition cycles have occurred.

Reference Information

Schematic Reference

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

Connector End View Reference

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

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate driver seat motor listed below for which the DTC set:

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

2. Ignition ON.
3. Test for greater than 10.8 V between the 12 V reference circuit terminal 2 and ground.

If 10.8 V or less

1. Ignition OFF, disconnect the X1 harness connector at the K40 Seat Memory Control Module.
2. Test for infinite resistance between the 12 V reference circuit and ground.

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

3. Test for less than 2 ohms in the 12 V reference circuit end to end.

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

If greater than 10.8 V

4. Test for 0.2-2.0 V between the signal circuit terminal 4 and ground.

If less than 0.2 V

1. Ignition OFF, disconnect the X1 harness connector at the K40 Seat Memory Control Module.
2. Test for infinite resistance between the signal circuit and ground.

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

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

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

If greater than 2.0 V

1. Ignition OFF, disconnect the X1 harness connector at the K40 Seat Memory Control Module, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K40 Seat Memory Control Module.

If between 0.2-2.0 V

5. Test or replace the seat motor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

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

DTC B3920: Driver seat motors group 1

Diagnostic Instructions

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

DTC Descriptors

DTC B3920 00

Driver Seat Motors Group 1 Common Circuit Malfunction

DTC B3920 01

Driver Seat Motors Group 1 Common Circuit Short to Battery

DTC B3920 02

Driver Seat Motors Group 1 Common Circuit Short to Ground

DTC B3920 42

Driver Seat Motors Group 1 Common Circuit Calibration Not Programmed

DTC B3920 0B

Driver Seat Motors Group 1 Common Circuit High Current

Diagnostic Fault Information

Circuit/System Description

The seat memory control module controls the seat motors via half bridges that are connected to power rails internal to the module. The seat memory control module 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 V. The seat memory control module checks to see if this reference voltage is shorted to ground or battery before enabling any seat motor.

When a power seat switch is pressed or when a memory recall is requested, each seat motor receives battery voltage and ground from the seat memory control module via the motor control circuits. All motors are reversible, so the direction the motor rotates depends on which control circuit voltage is applied and which control circuit ground is applied. When the switch is operated in the opposite direction, the module reverses the polarity and applies voltage and ground to the opposite circuits to move the seat in the opposite direction.

Conditions for Running the DTC

• DTC B1325 must not be present.
• Module battery voltage must be between 9-16 V.

Conditions for Setting the DTC

B3920 00

Current out of the module does not match the current returning to the module from 1.5-5 A.

B3920 01

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

B3920 02

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

B3920 42

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

B3920 0B

The differential current measured through the high and low side of the power rail is within tolerance of each other, but the absolute current or an over-current has exceeded the maximum value.

Action Taken When the DTC Sets

The seat memory control module will not allow operation of any motor on the power rail for which the DTC was set.

Conditions for Clearing the DTC

• The current DTC clears when the fault is no longer present and the power mode changes to OFF then back to ACC or RUN.
• The history DTC will clear after 40 consecutive fault-free ignition cycles have occurred.

Reference Information

Schematic Reference

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

Connector End View Reference

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

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Testing

B3920 01 or B3920 02

1. Ignition OFF, disconnect the X4 and X5 harness connectors at the K40 Seat Memory Control Module.
2. Test for infinite resistance between the control circuit terminals listed below and ground:

• Front vertical motor up control terminal 7 X4
• Front vertical motor down control terminal 8 X4
• Rear vertical motor up control terminal 4 X5
• Rear vertical motor down control terminal 3 X5
• Horizontal motor forward control terminal 2 X5
• Horizontal motor rearward control terminal 1 X5

If less than infinite resistance

Repair the short to ground on the circuit.

If infinite resistance

3. Ignition ON.
4. Test for less than 1 V between the control circuit terminals listed below and ground:

• Front vertical motor up control terminal 7 X4
• Front vertical motor down control terminal 8 X4
• Rear vertical motor up control terminal 4 X5
• Rear vertical motor down control terminal 3 X5
• Horizontal motor forward control terminal 2 X5
• Horizontal motor rearward control terminal 1 X5

If 1 V or greater

Repair the short to voltage on the circuit.

If less than 1 V

5. Replace the K40 Seat Memory Control Module.

B3920 00 or B3920 0B

1. Ignition ON.
2. Clear the current and history DTC.
3. Determine which motor set this DTC by operating the driver seat motors listed below one at a time in both directions. Check for the DTC to set between each motor test.

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

4. Ignition OFF, disconnect the harness connector at the seat motor for which the DTC set, ignition ON.
5. Clear the DTC.
6.  Verify that DTC B3920 00 or B3920 0B does not set while operating the seat motor adjuster switch in both directions.

If DTC B3920 00 or B3920 0B sets

1. Test for infinite resistance between control circuit terminal 1 and control circuit terminal 5.

• If less than infinite resistance, repair the short between the circuits.
• If infinite resistance

2. Test for less than 2 ohms between the control circuit terminals listed below end to end:

• Terminal 1
• Terminal 5

If 2 ohms or greater, repair the open/high resistance in the circuit.

If less than 2 ohms, replace the seat motor.

If DTC B3920 00 or B3920 0B does not set

7. Replace the seat motor.

B3920 42

1. Ignition ON.
2. Verify the DTC is not set.

If the DTC is set

Replace the K40 Seat Memory Control Module.

If the DTC is not set

3. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

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

Symptoms - power seats

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

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

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

2. Review the system operation in order to familiarize yourself with the system functions. Refer to the following system descriptions:

• Lumbar Support Description and Operation
• Memory Seats Description and Operation
• Power Seats System Description and Operation

Visual/Physical Inspection

• Inspect for aftermarket devices which could affect the operation of the system. Refer to Checking Aftermarket Accessories .
• Inspect the easily accessible or visible system components for obvious damage or conditions which could cause the symptom.

Intermittent

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

Symptom List

Refer to a symptom diagnostic procedure from the following list in order to diagnose the symptom:

• Lumbar Support Malfunction
• Memory Seat Feature Malfunction
• Power Seat Malfunction (Without Memory A45), Power Seat Malfunction (With Memory A45)

LUMBAR SUPPORT MALFUNCTION

Diagnostic Instructions

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

Diagnostic Fault Information

Circuit/System Description

The seat lumbar support is controlled through the seat lumbar support switch. Battery voltage is supplied at all times to the lumbar switch through a 15 A fuse located in the rear body fuse block. When the lumbar switch is in an inactive state, the switch contacts are closed to the switch ground circuit.

The lumbar motor is reversible. For example, when the lumbar 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.

Reference Information

Schematic Reference

• Driver Seat Schematics (Encore), Driver Seat Schematics (Encore)
• Passenger Seat Schematics (Encore)

Connector End View Reference

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

Description and Operation

Lumbar Support Description and Operation

Electrical Information Reference

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

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate S65 Seat Lumbar Support Switch. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal H and ground.

If 10 ohms or greater

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

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

If less than 10 ohms

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

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

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

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

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

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

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

3. Test for greater than 10 ohms between each control circuit listed below and ground:

• Lumbar forward control circuit terminal A
• Lumbar rearward control circuit terminal D

If 10 ohms or less, disconnect the harness connector at the M53 Seat Lumbar Support Motor and retest to verify if the short is in the circuit or the component.

If greater than 10 ohms, test or replace the S65 Seat Lumbar Support Switch.

If the test lamp illuminates

5. Ignition OFF, connect the harness connector at the S65 Seat Lumbar Support Switch and disconnect the harness connector at the M53 Seat Lumbar Support Motor.
6. Connect a test lamp between control circuit terminal A and control circuit terminal B, ignition ON.
7. Verify the test lamp turns ON when commanding the lumbar support Forward and Rearward using the S65 Seat Lumbar Support Switch.

If the test lamp remains OFF during either of the commands

1. Ignition OFF, disconnect the harness connector at the S65 Seat Lumbar Support Switch.
2. Test for infinite resistance between each control circuit and ground.

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

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

• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the S65 Seat Lumbar Support Switch.

If the test lamp remains ON during either of the commands

1. Ignition OFF, disconnect the harness connector at the S65 Seat Lumbar Support Switch, ignition ON.
2. Test for less than 1 V between the signal circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the S65 Seat Lumbar Support Switch.

If the test lamp turns ON during each of the commands

8. Test or replace the M53 Seat Lumbar Support Motor.

Component Testing

Lumbar Support Switch

1. Ignition OFF, disconnect the harness connector at the appropriate S65 Seat Lumbar Support Switch.
2. Test for infinite resistance between the B+ terminal E and each control terminal with the switch in the open position.

If less than infinite resistance

Replace the S65 Seat Lumbar Support Switch.

If infinite resistance

3. Test for less than 2 ohms between the B+ terminal E and each control terminal with the appropriate switch in the closed position.

If 2 ohms or greater

Replace the S65 Seat Lumbar Support Switch.

If less than 2 ohms

4. Test for less than 2 ohms between the ground terminal H and each control terminal with the switch in the open position.

If 2 ohms or greater

Replace the S65 Seat Lumbar Support Switch.

If less than 2 ohms

5. All OK.

Seat Lumbar Support Motor

1. Ignition OFF, disconnect the harness connector at the M53 Seat Lumbar Support Motor.

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

2. Install a 30 A fused jumper wire between control terminal A 12 V.
3. Momentarily install a jumper wire between control terminal B and ground. The M53 Seat Lumbar Support Motor should momentarily perform the lumbar FORWARD function.

If the motor does not perform the lumbar FORWARD function

Replace the M53 Seat Lumbar Support Motor

If the motor performs the lumbar FORWARD function

4. Reverse the polarity of jumper wires; the lumbar motor should perform REARWARD function.

If the motor does not perform the lumbar REARWARD function

Replace the M53 Seat Lumbar Support Motor.

If the motor performs the lumbar REARWARD function

5. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Driver or Passenger Seat Lumbar Control Switch Replacement
• Driver or Passenger Seat Back Cushion Frame Replacement

Memory seat feature malfunction

Diagnostic Instructions

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

Diagnostic Fault Information

Circuit/System Description

Low reference is supplied to the driver seat memory switch from the seat memory control module. When a memory switch is pressed, the signal circuit from the seat memory control module is pulled low through the switch contacts and series of resistors indicating the memory recall request. In response to this signal, the seat memory control module commands the appropriate seat motors to move to the pre-recorded seat positions stored in memory.

Diagnostic Aids

The seat memory control module must be awake when measuring voltage from either one of the memory seat switch signal circuits. Voltage readings of 0.0 V or 5 V are possible if the module is not fully awake and result in misdiagnosing the circuit.

Reference Information

Schematic Reference

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

Connector End View Reference

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

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.
2. Verify that all manual driver power seat functions operate when being controlled by the power seat adjuster switches.

If any seat function does not operate

Refer to Power Seat Malfunction (Without Memory A45), Power Seat Malfunction (With Memory A45).

If all seat functions operate

3. Verify that the memory recall personalization option is ON. Refer to the owners manual.

If the memory recall personalization option is not ON

Turn ON the option, refer to the Owners Manual.

If the memory recall personalization option is ON

4. Refer to Circuit/System Testing.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the S47D Seat Memory Switch - Driver.
2. Test for less than 20 ohms between the low reference circuit terminal 1 and ground.

If 20 ohms or greater

1. Ignition OFF, disconnect the X2 harness connector at the K40 Seat Memory Control Module.
2. Test for less than 2 ohms in the low reference circuit end to end

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

If less than 20 ohms

3. Ignition ON, press a power seat switch in order to wake up the K40 Seat Memory Control Module.
4. Test for 9 V or greater between each signal circuit terminal listed below and ground:

• Memory set switch signal terminal 5
• Memory switch signal terminal 6

If less than 9 V

1. Ignition OFF, disconnect the X2 harness connector at the K40 Seat Memory Control Module.
2. Test for infinite resistance between the signal circuit and ground.

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

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

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

If 9 V or greater

5. Ignition OFF, disconnect the X2 harness connector at the K40 Seat Memory Control Module, ignition ON.
6. Test for less than 1 V between each signal circuit terminal listed below and ground:

• Memory set switch signal terminal 5
• Memory switch signal terminal 6

If 1 V or greater

Repair the short to voltage on the circuit.

If less than 1 V

7. Test or replace the S47D Seat Memory Switch - Driver.

Component Testing

Driver Seat Memory Switch

1. Ignition OFF, disconnect the harness connector at the S47D Seat Memory Switch - Driver.
2. Test for infinite resistance between each signal terminal listed below and the low reference terminal 5 with the switch in the open position.

• Terminal 1
• Terminal 6

If less than infinite resistance

Replace the S47D Seat Memory Switch - Driver.

If infinite resistance

3. Test for less than 2 ohms between the signal terminal 1 and the low reference terminal 5 while pressing the memory MEM button.

If 2 ohms or greater

Replace the S47D Seat Memory Switch - Driver.

If less than 2 ohms

4. Test for 570-698 ohms between the signal terminal 6 and the low reference terminal 5 while pressing the memory 1 button.

If not between 570-698 ohms

Replace the S47D Seat Memory Switch - Driver.

If between 570-698 ohms

5. Test for 1800-2209 ohms between the signal terminal 6 and the low reference terminal 5 while pressing the memory 2 button.

If not between 1800-2209 ohms

Replace the S47D Seat Memory Switch - Driver.

If between 1800-2209 ohms

6. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Driver Seat Adjuster Memory Switch Replacement (Encore)
• Control Module References for K40 Seat Memory Control Module replacement, programming and setup

Power seat malfunction (without memory A45)

Diagnostic Instructions

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

Diagnostic Fault Information

Circuit/System Description

Battery voltage is supplied at all times to the seat adjuster switch through a 30 A fuse located in the rear body fuse block. When the seat switch is in a 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, B+ is applied through the switch contacts and the seat horizontal motor forward control circuit to the motor. With the horizontal motor rearward switch contacts closed to the switch ground circuit, the motor runs in order to drive the entire seat forward until the switch is released. Moving the entire seat rearward works similarly to moving the entire seat forward, except that battery voltage and ground are applied on opposite circuits causing the motor to run in the opposite direction. All seat motors are powered this way.

Reference Information

Schematic Reference

• Driver Seat Schematics (Encore), Driver Seat Schematics (Encore)
• Passenger Seat Schematics (Encore)

Connector End View Reference

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

Description and Operation

Power Seats System Description and Operation

Electrical Information Reference

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

Circuit/System Verification

1. Verify the driver or passenger power seat directional motors listed below operate when operating the seat switches in both directions.

• M50 Seat Front Vertical Motor
• M51 Seat Horizontal Motor
• M55 Seat Rear Vertical Motor

If all seat motors do not operate

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

If 1 or more seat motors operate

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

2. All OK.

Circuit/System Testing

Seat Adjuster Switch Circuit Test

1. Ignition OFF, disconnect the harness connector at the appropriate S64 Seat Adjuster Switch.
2. Test for less than 10 ohms between the ground circuit terminal B and ground.

If 10 ohms or greater

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

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

If less than 10 ohms

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

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

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

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

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

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

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

3. Test for greater than 10 ohms between each signal circuit listed below and ground:

• Control circuit terminal E - M50 Seat Front Vertical Motor
• Control circuit terminal G - M50 Seat Front Vertical Motor
• Control circuit terminal A - M55 Seat Rear Vertical Motor
• Control circuit terminal H - M55 Seat Rear Vertical Motor
• Control circuit terminal F - M51 Seat Horizontal Motor
• Control circuit terminal C - M51 Seat Horizontal Motor

If 10 ohms or less, disconnect the harness connector at the seat motor and retest to verify if the short is in the circuit or the component.

If greater than 10 ohms, test or replace the S64 Seat Adjuster Switch.

If the test lamp illuminates

5. Test or replace the S64 Seat Adjuster Switch.

Seat Motor Circuit Test

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

• M51 Seat Horizontal Motor
• M50 Seat Front Vertical Motor
• M55 Seat Rear Vertical Motor

2. Connect a test lamp between control circuit terminal 1 and control circuit terminal 3, ignition ON.
3. Verify the test lamp turns ON when commanding the seat motor Up and Down or Forward and Rearward using the seat adjuster switch.

If the test lamp does not turn ON during either of the commands

1. Ignition OFF, disconnect the harness connector at the S64 Seat Adjuster Switch.
2. Test for less than 2 ohms in each control circuit end to end.

If 2 ohms or greater, repair the open/high resistance in the circuit.

If less than 2 ohms, test or replace the S64 Seat Adjuster Switch

If the test lamp turns ON during each of the commands

4. Test or replace the seat motor.

Component Testing

Seat Adjuster Switch

1. Ignition OFF, disconnect the harness connector at the S64 Seat Adjuster Switch.
2. Test for infinite resistance between the B+ terminal D and each control terminal with the switch in the open position.

If less than infinite resistance

Replace the S64 Seat Adjuster Switch.

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

If 2 ohms or greater

Replace the S64 Seat Adjuster Switch.

If less than 2 ohms

4. Test for less than 2 ohms between the ground terminal B and each control terminal listed below with the switch in the open position.

If 2 ohms or greater

Replace the S64 Seat Adjuster Switch.

If less than 2 ohms

5. All OK.

Seat Motor

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

• M51 Seat Horizontal Motor
• M50 Seat Front Vertical Motor
• M55 Seat Rear Vertical Motor

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

2. Install a 30 A fused jumper wire between control terminal 1 and 12 V.
3. Momentarily install a jumper wire between control terminal 3 and ground. The seat motor should momentarily perform the appropriate FORWARD/ REARWARD/ UP/ DOWN function.

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

Replace the motor.

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

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

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

Replace the motor.

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

5. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Driver or Passenger Seat Adjuster Switch Replacement
• Front Seat Tilt Adjuster Actuator Replacement
• Driver or Passenger Seat Vertical Adjuster Actuator Replacement
• Front Seat Adjuster Actuator Replacement

Power seat malfunction (with memory A45)

Diagnostic Instructions

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

Diagnostic Fault Information

Circuit/System Description

Battery voltage is supplied at all times to the seat memory control module through a 25 A fuse located in the underhood fuse block. This voltage is used by the module for logic power. Battery positive voltage is also supplied at all times to the seat memory control module through a 30 A fuse located in the rear body fuse block.

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

All motors are reversible. For example, when the seat switch is operated to move the entire seat forward, the switch signal circuit from the seat memory control module is pulled low indicating the entire seat forward command. In response to this signal, the seat memory control module applies battery voltage through the driver seat horizontal motor forward control circuit and ground through the driver seat horizontal motor rearward control circuit to the motor. The motor runs to drive the entire seat forward until the switch is released. Moving the entire seat rearward works similarly to moving the entire seat forward, except that battery positive voltage and ground are applied on the opposite circuits causing the motor to run in the opposite direction.

Reference Information

Schematic Reference

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

Connector End View Reference

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

Description and Operation

Memory Seats Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.
2. Verify the scan tool seat switch parameters listed below change between Inactive and Forward/Rearward or Up/Down when pressing the appropriate switch.

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

If the parameter does not change

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

If the parameter changes

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

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

If any seat motor does not operate

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

If all seat motors operate

4. All OK.

Circuit/System Testing

Driver Seat Adjuster Switch Circuit Test

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the S64D Seat Adjuster Switch - Driver. It may take up to 2 min for all vehicle systems to power down.
2. Test for less than 10 ohms between the ground circuit terminal D and ground.

If 10 ohms or greater

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

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

If less than 10 ohms

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

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

If not Inactive

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

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

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

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

If Inactive

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

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

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

If not Forward/Rearward or UP/Down

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

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

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

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

If Forward/Rearward or UP/Down

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

Seat Motor Control Circuit Test

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

If 10 ohms or greater

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

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

If less than 10 ohms

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

If the test lamp does not illuminate

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

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

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

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

If the test lamp illuminates

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

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

6. Connect a test lamp between control circuit terminal 1 and control circuit terminal 3, ignition ON.

NOTE: Once a seat motor is commanded On using the scan tool, the seat function may not work using the seat adjuster switch until you back out of the scan tool Control Functions menu.

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

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

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

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

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

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

If the test lamp illuminates during each of the commands

8. Test or replace the seat motor.

Component Testing

Seat Adjuster Switch Test

1. Ignition OFF, disconnect the harness connector at the S64D Seat Adjuster Switch - Driver.
2. Test for infinite resistance between the ground terminal D and each signal terminal with the switch in the open position.

If less than infinite resistance

Replace the S64D Seat Adjuster Switch - Driver.

If infinite resistance

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

If 2 ohms or greater

Replace the S64D Seat Adjuster Switch - Driver.

If less than 2 ohms

4. All OK.

Seat Motor

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

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

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

2. Install a 30 A fused jumper wire between control terminal 1 and 12 V.
3. Momentarily install a jumper wire between control terminal 3 and ground. The seat motor should momentarily perform the appropriate FORWARD/ REARWARD/ UP/ DOWN function.

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

Replace the motor.

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

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

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

Replace the motor.

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

5. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair

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

READ NEXT: