For 1990-2009 cars

### 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 | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
12-Volt Reference | 1 | 1 | -- | --
Memory Switch Signal | 1 | 1 | 1 | --
1. Memory seat feature inoperative

### Circuit/System Description

Reference voltage is supplied to the memory switch from the driver door module (DDM). When a memory switch is pressed, reference voltage is applied through the switch contacts, a series of resistors and thorough the memory switch signal circuit to the DDM. The door module then sends a serial data message 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.

### Diagnostic Aids

The DDM is referenced in Tech 2 as the Driver Door Switch.

### Reference Information

#### Schematic Reference

Driver Seat Schematics

#### Connector End View Reference

Component Connector End Views

#### 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. Verify that all manual power seat and lumbar functions operate when being controlled by the seat adjuster and lumbar switches.

⇒ | If any seat or lumbar function does not operate, refer to Power Seat Inoperative or Lumbar Support Inoperative .

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

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the memory seat switch.
2. Ignition ON, verify a test lamp illuminates between a reference voltage circuit terminal 2 and ground.

⇒ | If the test lamp does not illuminate, test the reference voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the DDM.

3. Test for less than 1 volt between the signal circuit terminal 1 and ground.

⇒ | If greater than a specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the DDM.

4. Ignition OFF, connect the harness connector at the memory seat switch.
5. Ignition ON, verify the scan tool Driver Door Switch Memory Recall Switches parameter is approximately 2.75 volts while pressing the memory 1 switch.

⇒ | If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the memory seat switch.

6. Verify the scan tool Memory Recall Switches parameter is approximately 1.75 volts while pressing the memory 2 switch.

⇒ | If not the specified value, test or replace the memory seat switch.

7. Verify the scan tool Memory Recall Switches parameter is approximately 1.0 volt while pressing the EXIT switch.

⇒ | If not the specified value, test or replace the memory seat switch.

8. If all circuits test normal, replace the MSM.

### Component Testing

#### Memory Switch

1. Disconnect the harness connector at the memory seat switch.
2. Test for infinite resistance between the memory switch signal circuit terminal 1 and the switch supply voltage circuit terminal 2.

⇒ | If not infinite, replace the memory seat switch.

3. Test the resistance between terminal 1 and terminal 2 while pressing the memory 1, memory 2, and EXIT buttons. 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 seat switch.

#### Memory Switch Values

Switch Position | Resistance
--- | ---
Idle | Infinite
Memory 1 | 2.03K-2.49K Ω
Memory 2 | 3.83K-4.69K Ω
EXIT | 8.33K-10.18K Ω

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Driver Seat Adjuster Memory Switch Replacement

• | Control Module References for MSM and DDM replacement, setup, and programming