GM Service Manual Online
For 1990-2009 cars only

Diagnostic Aids

The key cylinder switches are contained within the driver door lock actuator and are part of the Central Door Unlocking and Central Door Locking and Deadbolt features. The switches are not serviced separately from the door lock actuators. Domestic vehicles are equipped with the Central Door Unlocking feature while export vehicles may be equipped with, either the Central Door Locking, or Central Door Locking and Deadbolt feature. For more information concerning these features, refer to Power Door Locks Description and Operation

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step inspects to see that the driver door module recognizes the key cylinder switch input.

Step

Action

Yes

No

Schematic Reference: Door Lock/Indicator Schematics

Connector End View Reference: Power Door Systems Connector End Views

DEFINITION: The doors do not unlock from the driver door key lock cylinder or the doors do not lock from the driver door key lock cylinder. This test assumes that all DTCs have been diagnosed.

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

Verify that the Power Door Locks Inoperative - Key Cylinder Switches complaint is present.

Does the Central Door Lock and Central Door Unlock systems 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. Turn ON the ignition, with the engine OFF.
  3. With the scan tool, observe the Key Cylinder Lock/Unlock parameter in the Driver Door Module, Inputs list.
  4. If the vehicle is equipped with the Central Door Lock feature, insert the door key into the driver door lock cylinder, turn it to the lock position, and hold it there for 3-5 seconds.
  5. If the vehicle is equipped with the Central Door Unlock feature, insert the door key into the driver door lock cylinder, turn it to the Unlock position and hold it there for 3-5 seconds.

Does the Key Cylinder Lock/Unlock parameter change to the appropriate state as expected?

Go to Step 8

Go to Step 4

4

  1. Turn OFF the ignition.
  2. Disconnect the driver door lock actuator harness connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Install a 3-amp fused jumper wire between the appropriate key cylinder switch signal circuit of the harness connector and a good ground.
  5. With the scan tool, observe the Key Cylinder Lock/Unlock parameter.

Does the Key Cylinder Lock/Unlock parameter change to the appropriate state?

Go to Step 5

Go to Step 6

5

  1. Install a 3-amp fused jumper wire between the appropriate key cylinder switch signal and ground circuits of the harness connector.
  2. With the scan tool, observe the Key Cylinder Lock/Unlock parameter.

Does the Key Cylinder Lock/Unlock parameter change to the appropriate state?

Go to Step 7

Go to Step 9

6

Test the appropriate key cylinder switch signal circuit for an open or 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 8

7

Inspect for poor connections at the harness connector of the driver door lock actuator. 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

8

Inspect for poor connections at the appropriate harness connector of the driver door module (DDM). 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

9

Repair the open ground circuit of the harness connector. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 12

--

10

Replace the driver door lock actuator. Refer to Front Side Door Latch Replacement .

Did you complete the replacement?

Go to Step 12

--

11

Important: Perform the setup procedure for the replacement door module. Refer to Door Control Module Programming and Setup in Programming and Setup.

Replace the DDM. Refer to Control Module References in Computer/Integration Systems.

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