For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
DEFINITION: The door key cylinder unlock feature is inoperative when unlocking 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. Connect a test lamp 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 the BCM connector C2.
3. Use a J 39200 digital multimeter (DMM) in order to measure the resistance between the key cylinder lock switch harness connector terminal D (terminal B when checking the liftgate lock) and the BCM harness connector C2 terminal C5.

Is the resistance less than the specified value?

10ohms

Go to Step 4

Go to Step 6

4 |

1. Insert a key in the inoperative door cylinder lock. Rotate the lock to the unlock position.
2. Use a J 39200 DMM in order to measure the resistance between the door lock cylinder switch connector terminal C and terminal D (terminals B and C when checking the liftgate lock cylinder).

Is the resistance less than the specified value?

2ohms

Go to Step 7

Go to Step 8

5 | Repair the poor connection or the open in CKT 750. Is the repair complete? | -- | Go to Step 9 | --
6 | Repair the poor connection or the open in CKT 781. 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 Systems

Is the repair complete?

--

Go to Step 9

--

8 | Replace the key cylinder lock switch. Refer to Door Lock Cylinder Replacement or Lock Cylinder Replacement - Sliding Door . Is the repair complete? | -- | Go to Step 9 | --
9 |

1. Turn the ignition switch to the LOCK position.
2. Re-install the connectors/components that were 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. Turn the ignition switch from the ACC position, to the LOCK position and back to the ACC position within 1 second. (The BCM sounds any DTCs stored).

Are there any BCM DTCs present?

--

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

Go to Automatic Door Locks System Check