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
--- | --- | --- | --- | ---
Lock Relay and Unlock Relay B+ | 2 | 2 | -- | --
Driver Door Lock Switch Lock Signal | B3150 00 | B3150 00 | B3150 00 | --
Driver Door Lock Switch Unlock Signal | B3140 00 | B3140 00 | B3140 00 | --
Passenger Door Lock Switch Lock Signal | B3155 00 | B3155 00 | B3155 00 | --
Passenger Door Lock Switch Unlock Signal | B3145 00 | B3145 00 | B3145 00 | --
Driver Door Latch Control | 2 | 2 | 2 | --
Door Unlock Relay Control | B3130 00 | B3130 00 | B3130 00 | --
Driver Door Relay Unlock Control | B3125 00 | B3125 00 | B3125 00 | --
Door Lock Relay Control | B3135 00 | B3135 00 | B3135 00 | --
Passenger Door Latch Control | 2 | 2 | 2 | --
Driver Door Lock Switch Ground | -- | 1 | 1 | --
Lock Relay and Unlock Relay Ground | -- | 2 | 2 | --
Passenger Door Lock Switch Ground | -- | 1 | 1 | --
1. Door Lock Switch Malfunction 2. Door Latch Malfunction

### Circuit/System Description

The body control module (BCM), upon receipt of a lock switch lock signal, will switch the door lock relay control circuit to battery positive voltage. This will energize the LOCK relay. The remaining unlock relays receive voltage from the underhood fuse block, the BCM upon receipt of a unlock signal or driver door unlock signal will switch the appropriate unlock relay to ground. This will energize the appropriate unlock relay unlocking the appropriate doors.

### Conditions for Running the DTC

The system voltage must be between 9-16 volts.

### Conditions for Setting the DTC

#### B3125 00

The BCM detects a fault in the driver door unlock control circuit while commanding the DRIVER UNLOCK relay.

#### B3130 00

The BCM detects a fault in the door unlock control circuit while commanding the UNLOCK relay.

#### B3135 00

The BCM detects a fault in the door lock control circuit while commanding the LOCK relay.

### 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 be 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

Command the driver door and passenger door latches to LOCK and UNLOCK with the scan tool, the doors should perform LOCK and UNLOCK functions.

### Circuit/System Testing

#### Door Lock Malfunction

1. Igniton OFF, disconnect the X3 harness connector at the the I/P fuse block.
2. Connect a test lamp between the control circuit terminal 42 and ground.
3. Ignition ON, command the Lock Rear Doors ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

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

⇒ | 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.

4. Connect a test lamp between the control circuit terminal 41 and B+.
5. Command the Unlock Rear Doors ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

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

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

6. Connect a test lamp between the control circuit terminal 8 and B+.
7. Command the Driver Door Unlock ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

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

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

8. If all circuits test normal, replace the I/P fuse block.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Instrument Panel Electrical Center or Junction Block Replacement

• | Control Module References for BCM replacement, setup and programming