For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
DEFINITION: The door key cylinder lock feature is inoperative when locking doors using the door key cylinder.
1 | Was the Body Control Module Diagnostic System Check performed? | -- | Go to Step 2 | Go to Diagnostic System Check - Body Control System in Body Control System
2 |

1. Disconnect the inoperative key cylinder lock switch electrical connector.
2. Use a test lamp to backprobe between B+ and the key cylinder lock switch harness connector terminal C.

Does the test lamp light?

--

Go to Step 3

Go to Step 5

3 |

1. Turn the ignition switch to the LOCK position.
2. Disconnect BCM connector C2.
3. Using a J 39200 DMM, measure the resistance between the key cylinder lock switch harness connector terminal A and the BCM harness connector C2 terminal C11.

Is the resistance less than the specified range?

10 ohms

Go to Step 4

Go to Step 6

4 |

1. Insert key in inoperative door cylinder lock and rotate lock to unlock position.
2. Using a J 39200 DMM, measure the resistance between the door lock cylinder switch connector terminals A and C.

Is the resistance less that the specified range?

2 ohms

Go to Step 7

Go to Step 8

5 | Repair poor connection or open in CKT 750. Is the repair complete? | -- | Go to Step 9 | --
6 | Repair poor connection or open in CKT 780. Is the repair complete? | -- | Go to Step 9 | --
7 |

1. Inspect the BCM connector C2 terminal C5 for poor terminal contact.
2. If the BCM connector C2 terminal C5 is OK, replace the BCM. Refer to Body Control Module Replacement in Body Control Systems.

Is the repair complete?

--

Go to Step 9

--

8 | Replace the key lock cylinder switch. Refer to Door Lock Cylinder Replacement in Doors or Lock Cylinder Replacement - Liftgate in Body Rear End. Is the repair complete? | -- | Go to Step 9 | --
9 |

1. Turn the ignition switch to the LOCK position.
2. Reinstall connectors/components removed.
3. Turn the ignition switch to the RUN position for 6 seconds.
4. Turn the ignition switch to the LOCK position.
5. Remove the BCM PRGRM fuse.
6. Turn the ignition switch to the ACC position. (The BCM sounds the chime a number of times equivalent to the BCM type installed on the vehicle).
7. Within one second, turn the ignition switch from the ACC position, to the LOCK position, then back to the ACC position. (The BCM sounds and DTCs stored).

Are there any BCM DTCs present?

--

Go to Diagnostic System Check - Body Control System in Body Control System

System OK