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 B3125 00: Left Front/Driver Door Only Unlock Circuit
DTC B3130 00: All Door Unlock Circuit
DTC B3135 00: All Door Lock Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
I/P Fuse Block B+ | 1 | 1 | -- | --
Door Lock Switch Lock Signal | B3150 00 | 2 | 2 | --
Door Lock Switch Unlock Signal | B3140 00 | 2 | 2 | --
All Lock Relay Control | B3135 00 | B3135 00 | 1 | --
Door Latch Assembly Control | 1 | 1 | 1 | --
Driver Unlock Relay Control | B3125 00 | B3125 00 | B3125 00 | --
Passenger Unlock Relay Control | B3130 00 | B3130 00 | B3130 00 | --
Window/Door Lock Switch Ground | -- | 2 | 2 | --
Relay Ground | -- | 1 | 1 | --
1. Door Lock Malfunction 2. Door Lock Switch Malfunction

### Circuit/System Description

The body control module (BCM) controls the door lock, passenger door unlock and driver door unlock relays. Voltage is applied to the appropriate relay through the door lock/unlock control circuit when the BCM detects a door lock/unlock switch activation or a keyless entry lock or unlock command.

### Conditions for Running the DTC

The system voltage is 9-16 volts.

### Conditions for Setting the DTC

#### B3125 00

The BCM detects a fault on the DRVR DR/UNLCK relay control circuit.

#### B3130 00

The BCM detects a fault on the PASS DR/UNLCK relay control circuit.

#### B3135 00

The BCM detects a fault on the DR/LCK relay control circuit.

### Action Taken When the DTC Sets

The power door locks will malfunction.

### Conditions for Clearing the DTC

• | The DTC will be current for as long as the fault is present.

• | When the fault is no longer present, the DTC will become a history DTC.

• | A history DTC will clear after 50 ignition cycles.

### Reference Information

#### Schematic Reference

Door Lock/Indicator Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Power Door Locks 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, command the All Doors Unlock/Lock with the scan tool, all doors should perform the LOCK and UNLOCK function.

⇒ | If B3125 00 is set, refer to DRVR DR/UNLCK Relay Control Malfunction.

⇒ | If B3130 00 is set, refer to PASS DR/UNLCK Relay Control Malfunction.

⇒ | If B3135 00 is set, refer to DR/LCK Relay Control Malfunction.

### Circuit/System Testing

#### DRVR DR/UNLCK Relay Control Malfunction

1. Ignition OFF, disconnect the DRVR DR/UNLCK relay.
2. Connect a test lamp between the control circuit terminal 85 and the B+ circuit terminal 86.
3. Ignition ON, command the Driver Door Unlock with a scan tool. The test lamp should briefly illuminate when commanding the UNLOCK state.

⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.

4. If all circuits test normal, test or replace the DRVR DR/UNLCK relay.

#### PASS DR/UNLCK Relay Control Malfunction

1. Ignition OFF, disconnect the PASS DR/UNLCK relay.
2. Connect a test lamp between the control circuit terminal 85 and the B+ circuit terminal 86.
3. Ignition ON, command the All Doors Unlock with a scan tool. The test lamp should briefly illuminate when commanding the UNLOCK state.

⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the BCM.

4. If all circuits test normal, test or replace the PASS DR/UNLCK relay.

#### DR/LCK Relay Control Malfunction

1. Ignition OFF, disconnect the DR/LCK relay.
2. Connect a test lamp between the control circuit terminal 85 and the ground circuit terminal 86.
3. Ignition ON, command the All Doors Lock with a scan tool. The test lamp should briefly illuminate when commanding the LOCK state.

⇒ | If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.

4. If all circuits test normal, test or replace the DR/LCK relay.

### Component Testing

1. Ignition OFF, disconnect the appropriate relay.
2. Test for 60-200 Ω between terminals 85 and 86.

⇒ | If not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

• | 30 and 86

• | 30 and 87

• | 30 and 85

• | 85 and 87

⇒ | If less than the specified value, replace the relay.

4. Test for less than 2 Ω between terminals 30 and 87A.

⇒ | If greater than the specified range, replace the relay.

5. Install a 3A fused jumper wire between relay terminal 85 and 12V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 Ω between terminals 30 and 87.

⇒ | If greater than specified range, replace the relay

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Relay Replacement

Control Module References for BCM replacement, setup, and programming