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

1

Did you perform the Door Systems Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Door Systems

2

Verify that the power door locks key cylinder switches inoperative fault is present.

Does the power door locks key cylinder switches system operate normally?

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

Go to Step 3

3

Does the power door locks system operate normally?

Go to Step 4

Go to Symptoms - Doors

4

  1. Close all of the doors.
  2. Install a scan tool.
  3. With the scan tool, observe the appropriate LF or RF Key Cylinder Lock Switch parameter in the Data Display, Inputs list of the body control module (BCM).

Does the Key Cylinder Lock Switch parameter display the Idle state?

Go to Step 5

Go to Step 6

5

  1. Insert the door key into the inoperative door lock cylinder switch.
  2. With the scan tool, observe the appropriate LF or RF Key Cylinder Lock Switch parameter in the Data Display, Inputs list of the body control module (BCM).
  3. Turn the door key cylinder first to the Lock position, and then to the Unlock position.

Did the Key Cylinder Lock Switch parameter change from the Idle state to the Lock and Unlock states as expected?

Go to Step 12

Go to Step 7

6

Disconnect the harness connector of the suspect door lock cylinder switch.

Does the Key Cylinder Lock Switch parameter display the Idle state?

Go to Step 11

Go to Step 9

7

  1. Disconnect the harness connector of the suspect door lock cylinder switch.
  2. Connect a 3 amp fused jumper wire between the appropriate key switch lock or unlock signal circuit of the harness connector and a good ground.
  3. With the scan tool, observe the appropriate Key Cylinder Lock Switch parameter.

Did the Key Cylinder Lock Switch parameter display the appropriate state?

Go to Step 8

Go to Step 10

8

  1. Connect the 3 amp fused jumper wire between the appropriate key switch lock or unlock signal circuit and the ground circuit of the harness connector.
  2. With the scan tool, observe the appropriate Key Cylinder Lock Switch parameter.

Did the Key Cylinder Lock Switch parameter display the appropriate state?

Go to Step 11

Go to Step 13

9

Test the appropriate door lock cylinder switch signal circuit 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 16

Go to Step 12

10

Test the appropriate door lock cylinder switch signal circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 16

Go to Step 12

11

Inspect for poor connections at the harness connector of the appropriate door lock cylinder 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 16

Go to Step 14

12

Inspect for poor connections at the harness connector of the body control module. 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 16

Go to Step 15

13

Repair the open ground circuit of the door lock cylinder switch. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 16

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14

Replace the appropriate door lock cylinder switch. Refer to Door Lock Cylinder Replacement .

Did you complete the replacement?

Go to Step 16

--

15

Replace the body control module. Refer to Body Control Module Replacement .

Did you complete the replacement?

Go to Step 16

--

16

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2