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 CircuitDTC B3130 00: All 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, 2, 3 | 1, 2, 3 | -- | -- |
Door Latch Control | 1, 2, 3 | 1, 2, 3 | 1, 2, 3 | -- |
Doors Unlock Control | B3130 00 | B3130 00 | B3130 00 | -- |
LF Door Unlock Control | B3125 00 | B3125 00 | B3125 00 | -- |
Doors Locked Control | B3135 00 | B3135 00 | -- | -- |
Left Lock Switch Signal | B3150 00 | B3150 00 | B3150 00 | -- |
Left Unlock Switch Signal | B3140 00 | B3140 00 | B3140 00 | -- |
Right Lock Switch Signal | B3155 00 | B3155 00 | B3155 00 | -- |
Right Unlock Switch Signal | B3145 00 | B3145 00 | B3145 00 | -- |
Door Lock Switch Ground | -- | 1, 2, 3 | 1, 2, 3 | -- |
I/P Fuse Block Ground | -- | 1, 2, 3 | 1, 2, 3 | -- |
1. Door Lock Malfunction 2. Driver Door Unlock Malfunction 3. Door Unlock Malfunction | ||||
Circuit/System Description
For vehicles without the RPO AXC/AXE door lock system, 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 senses a door lock/unlock switch activation or a keyless entry lock or unlock command.
For vehicles with the RPO AXC/AXE door lock system, the BCM controls the rear door lock and rear door unlock relays. Voltage is applied to the appropriate relay through the door lock/unlock control circuit when the BCM receives a door lock/unlock command from either the driver door module or the passenger door module or a keyless entry lock or unlock command.
Conditions for Running the DTC
The system voltage is 9-18 volts.
Conditions for Setting the DTC
B3125 00
The BCM detects a short to ground on the LT/UNLCK relay control circuit.
B3130 00
The BCM detects a short to ground on the UNLCK relay control circuit.
B3135 00
The BCM detects a short to ground on the LCK relay control circuit.
Action Taken When the DTC Sets
The power door locks will be inoperative.
Conditions for Clearing the DTC
| • | This 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
Vehicle Access Connector End Views
Description and Operation
Power Door Locks Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Command the driver door and passenger door lock actuators to LOCK and UNLOCK with the scan tool, the doors should perform the LOCK and UNLOCK function.
| ⇒ | If B3125 00 is current, refer to LT/UNLCK Relay Control Circuit Malfunction. |
| ⇒ | If B3130 00 is current, refer to UNLCK Relay Control Circuit Malfunction. |
| ⇒ | If B3135 00 is current, refer to LCK Relay Control Circuit Malfunction |
Circuit/System Testing
LT/UNLCK Relay Control Circuit Malfunction
- Ignition OFF, disconnect the LT/UNLCK relay.
- Connect a test lamp between the control circuit terminal 85 and the B+ circuit terminal 86.
- Ignition ON, command the driver door to UNLOCK with a scan tool. The test lamp should briefly illuminate when commanding the UNLOCK state.
- If all circuits test normal, test or replace the LT/UNLCK relay.
| ⇒ | 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. |
UNLCK Relay Control Circuit Malfunction
- Ignition OFF, disconnect the UNLCK relay.
- Connect a test lamp between the control circuit terminal 85 and the B+ circuit terminal 86.
- Ignition ON, command the rear doors to UNLOCK with a scan tool. The test lamp should briefly illuminate when commanding the UNLOCK state.
- If all circuits test normal, test or replace the UNLCK relay.
| ⇒ | 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. |
LCK Relay Control Circuit Malfunction
- Ignition OFF, disconnect the LCK relay.
- Connect a test lamp between the control circuit terminal 85 and the ground circuit terminal 86.
- Ignition ON, command the rear doors LOCK with a scan tool. The test lamp should briefly illuminate when commanding the LOCK state.
- If all circuits test normal, test or replace the LCK relay.
| ⇒ | 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. |
Component Testing
- Ignition OFF, disconnect the appropriate relay.
- Test for 60-200 ohms between terminals 85 and 86.
- Test for infinite resistance between the following terminals:
- Test for less than 2 ohms between terminals 30 and 87A.
- Install a 3A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.
| ⇒ | If not within the specified range, replace the relay. |
| • | 30 and 86 |
| • | 30 and 87 |
| • | 30 and 85 |
| • | 85 and 87 |
| ⇒ | If less than the specified value, replace the relay. |
| ⇒ | If greater than the specified range, replace the relay. |
| ⇒ | If greater than the specified range, replace the relay. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup and programming |
