GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Door Lock/Indicator Schematics

Connector End View Reference: Power Door Systems Connector End Views or Computer/Integrating Systems Connector End Views in Computer/Integrating Systems

DEFINITION: This diagnostic table should be used to diagnose a complete failure of the power door lock system.

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Activate both door lock switches to lock and unlock positions.

Did any of the doors lock and unlock from either door lock switch?

Go to Symptoms - Doors

Go to Step 3

3

Did all of the doors lock and unlock from both switches?

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

Go to Step 4

4

  1. Install a scan tool.
  2. Monitor the Door Lock Switch and Decoded Switch State data parameters.

Do both data parameters show an active switch state?

Go to Step 5

Go to Step 7

5

Test both door lock switch signal circuits for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 10

Go to Step 6

6

Inspect for poor connections at the faulty door lock switch. 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 10

Go to Step 8

7

Inspect for poor connections at the faulty body control module (BCM). 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 10

Go to Step 9

8

Replace the faulty door lock switch. Refer to Door Lock Switch Replacement .

Did you complete the repair?

Go to Step 10

--

9

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 10

--

10

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2