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 | -- | -- |
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 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 | -- | -- |
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
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.
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
Description and Operation
Power Door Locks Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
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.
- 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.
- 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.
- 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 |
