GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2000 🢒 Yukon - 4WD 🢒 Body and Accessories 🢒 Doors 🢒 Automatic Door Locks - Lock Inoperative

Step

Action

Yes

No

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 Power Door Locks Operation .

1

Did you perform the Power Door Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Power Door Systems

2

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

3
  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

4
  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 BCM.

Does the scan tool display the correct MPH?

Go to Step 5

Go to Step 8

5

Did the doors lock?

Go to Step 6

Go to Step 10

6
  1. Apply the brakes to stop the drive wheels.
  2. Place the transmission in PARK.
  3. Turn the engine OFF.
  4. Remove the ignition key.

Did the doors unlock?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 9

7

Check 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 11

Go to Step 10

8

Check for an open in the VSS signal circuit.

Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

9

Check 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 11

Go to Step 10

10

Replace the BCM.

Refer to Body Control Module Replacement in Body Control System.

Did you complete the repair?

Go to Step 11

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11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3