Schematic Reference: Door Lock/Indicator Schematics

Important: The automatic door lock system can be programed to perform different functions and may also be disabled. Before continuing with the diagnosis of the system, ensure that the automatic door locks are programmed to perform the specific function that is the cause of the complaint. For further information, refer to Vehicle Personalization in Personalization.

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

Lock and unlock the doors from any of the door lock switches.

Does the door lock system function properly?

Go to Step 3

Go to Symptoms - Doors

1. Install the scan tool.
2. Using output controls, command the doors to lock and unlock.

Do the doors lock and unlock when commanded?

Go to Step 4

Go to Step 7

1. Raise and support the vehicle.
2. Start the engine.
3. Place the transmission in gear.
4. Accelerate slowly to 20 mph and hold the speed.
5. Using the scan tool, monitor the vehicle speed in the body control module (BCM).

Does the scan tool display the correct mph?

Go to Step 5

Go to Step 8

Did the doors lock?

Go to Step 6

Go to Step 11

1. Apply the brakes to stop the drive wheels.
2. Place the transmission in Neutral.
3. Turn the engine OFF.
4. Remove the ignition key.

Did the doors unlock?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 9

Test for an open in the door lock and door unlock control circuits. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 10

Test for an open or high resistance in the vehicle speed sensor (VSS) signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 10

Test for a short to ground in the key in ignition switch signal circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 10

Inspect for poor connections at the BCM harness connectors. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 12

Go to Step 11

Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the repair?

Go to Step 12

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3