Diagnostic Routine E

Diagnostic Routine E

Diagnostic Overview

B126A:01

Refer to Wiring Diagram Set 117 for schematic and connector information Electrical Diagrams.

Normal Operations and Fault Conditions

The BCM (Body Control Module) sends voltage signals to the door lock control switches through the lock and unlock input circuits. When the lock or unlock switch is pressed, the corresponding voltage signal is routed to ground, signaling the BCM (Body Control Module) to lock or unlock the doors. The door lock control switches have a dedicated ground circuit. The BCM (Body Control Module) sends the lock or unlock request from the door lock control switch to the RFA (Remote Function Actuator) module over the MS-CAN (Medium Speed Controller Area Network).

DTC Fault Trigger Conditions






Visual Inspection and Diagnostic Pre-checks

- Door lock control switches

Pinpoint Test

1. CHECK THE LH (Left Hand) DOOR LOCK CONTROL SWITCH

1. Disconnect: LH (Left Hand) Door Lock Control Switch.

2. Using a scan tool, clear the BCM (Body Control Module) DTCs (Diagnostic Trouble Codes).

3. Using a scan tool, perform the BCM (Body Control Module) self-test.

Is DTC (Diagnostic Trouble Code) B126A:01 retrieved?








2. CHECK THE RH (Right Hand) DOOR LOCK CONTROL SWITCH

1. Disconnect: RH (Right Hand) Door Lock Control Switch.

2. Using a scan tool, clear the BCM (Body Control Module) DTCs (Diagnostic Trouble Codes).

3. Using a scan tool, perform the BCM (Body Control Module) self-test.

Is DTC (Diagnostic Trouble Code) B126A:01 retrieved again?








3. CHECK THE LOCK INPUT CIRCUIT OR THE UNLOCK INPUT CIRCUIT FOR A SHORT TO GROUND

1. Ignition OFF.

2. Disconnect: BCM (Body Control Module) C2280C.

3. Measure:





Are the resistances greater than 10,000 ohms?








4. CHECK FOR CORRECT BCM (Body Control Module) OPERATION

1. Ignition OFF.

2. Disconnect and inspect all BCM (Body Control Module) connectors.

3. Repair:

- corrosion (install new connector or terminals- clean module pins)
- damaged or bent pins- install new terminals/pins
- pushed-out pins- install new pins as necessary

4. Reconnect all BCM (Body Control Module) connectors. Make sure they seat and latch correctly.

5. Operate the system and determine if the concern is still present.

Is the concern still present?