GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

Schematic Reference: Door Lock/Indicator Schematics

DEFINITION: Door locks do not operate from one of the door lock cylinder switches, which are mounted to the inside of each door key cylinder in each door. This test assumes that all DTCs have been diagnosed.

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 Inoperative-Key Cylinder Switches complaint is present.

Does the power door locks Central Door Unlock system operate as described in the Description and Operation?

--

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

Go to Step 3

3

  1. Install a scan tool.
  2. With the scan tool, observe the Door Key Cyl. Unlock Sw. parameter in the Body Control Module Inputs list.

Does the Door Key Cyl. Unlock Sw. parameter display OFF?

--

Go to Step 4

Go to Step 7

4

  1. Insert the door lock key into the suspect door key cylinder, turn it to the Unlock position and hold it there for 3 to 5 seconds.
  2. With the scan tool, observe the Door Key Cyl. Unlock Sw.parameter in the Body Control Module Inputs list.

Does the Door Key Cyl. Unlock Sw. parameter change state?

--

Go to Step 9

Go to Step 5

5

  1. Disconnect the harness connector of the suspect door key cylinder unlock switch.
  2. Install a 3 amp fused jumper between the door key switch signal circuit and the ground circuit of the harness connector.
  3. With the scan tool, observe the Door Key Cyl Unlock Sw. parameter.

Does the Door Key Cyl. Unlock Sw. parameter display Unlock?

--

Go to Step 8

Go to Step 6

6

Test the suspect door key cylinder unlock switch signal circuit and ground circuit for an open, or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

7

Test the suspect door key cylinder unlock 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 12

Go to Step 9

8

Inspect for poor connections at the harness connector of the suspect door key cylinder unlock 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 12

Go to Step 10

9

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 12

Go to Step 11

10

Replace the door key cylinder unlock switch. Refer to Door Lock Cylinder Replacement .

Did you complete the replacement?

--

Go to Step 12

--

11

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

Did you complete the replacement?

--

Go to Step 12

--

12

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2