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

### DTC Descriptors

DTC B3907 02: Button PCB Malfunction

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Seat Adjuster Memory Switch 12 Volt Reference | B3907 02, 1 | 1 | -- | --
Memory Seat Switch Signal 1 | 1 | 1 | B1390 01 | --
Memory Seat Switch Signal 2 | 1 | 1 | B1400 01 | --
Memory Seat Switch Signal 3 | 1 | 1 | B1410 01 | --
Memory Mirror Switch Signal | 1 | 1 | B2765 01 | 1
1. Memory recall is inoperative

### Circuit/System Description

Reference voltage from the seat interface module (SIM) is supplied at all times to the memory seat switch. When a memory recall switch is pressed, reference voltage is applied through the switch contacts and the signal circuit to the SIM indicating the memory recall request. The SIM serves as a interface and applies a reference voltage through the appropriate memory signal circuit to the memory seat module (MSM) indicating the memory seat request. The MSM then commands the driver seat motors and the exterior mirrors to move to the appropriate seat and mirror positions stored in memory.

### Conditions for Running the DTC

The SIM is powered.

### Conditions for Setting the DTC

The button PCB assembly is shorted to ground.

### Action Taken When the DTC Sets

The memory recall function is disabled.

### Conditions for Clearing the DTC

• | The current DTC clears when the fault is no longer present.

• | The history DTC will clear after 50 consecutive fault-free ignition cycles have occurred.

### 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

Ignition ON, observe the scan tool SIM Input parameters listed below while pressing the appropriate memory 1, 2, 3, and M switches. The readings should change between Inactive and Active.

• | Button 1 Input Status

• | Button 2 Input Status

• | Button 3 Input Status

• | Button M Input Status

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the memory seat switch.
2. Ignition ON, verify that a test lamp illuminates between the 12 V reference circuit terminal 6 and ground.

⇒ | If the test lamp does not illuminate, test the 12 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the SIM.

3. Ignition ON, verify the scan tool SIM Input parameters listed below are Inactive:

• | Button 1 Input Status

• | Button 2 Input Status

• | Button 3 Input Status

• | Button M Input Status

⇒ | If not the specified value, test the appropriate signal circuit for a short to voltage. If the circuit tests normal, replace the SIM.

4. Install a 3 A fused jumper wire between the 12 V reference circuit terminal 6 and the signal circuit terminals listed below. Verify the appropriate scan tool SIM Memory Button Input Status parameter is Active between each test.

• | Button 1 Input Status

• | Button 2 Input Status

• | Button 3 Input Status

• | Button M Input Status

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

5. If all circuits test normal, test or replace the memory seat switch.

### Component Testing

1. Ignition OFF, disconnect the harness connector at the memory seat switch.
2. Test for infinite resistance between the 12 V reference terminal 6 and each signal terminal listed below with the switch in the open position:

• | Memory 1 terminal 1

• | Memory 2 terminal 2

• | Memory 3 terminal 3

• | Memory M terminal 4

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

3. Test for less than 2 Ω between the 12 V reference terminal 6 and each signal terminal listed below with the appropriate switch in the closed position:

• | Memory 1 terminal 1

• | Memory 2 terminal 2

• | Memory 3 terminal 3

• | Memory M terminal 4

⇒ | If greater than the specified range, replace the memory seat switch.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Driver Seat Adjuster Memory Switch Replacement

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