Central Door Unlock

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.

The vehicle may be equipped with the central door unlock feature. With this feature, all doors can be unlocked from the driver door using the door key. To operate the feature, the door key is inserted into the driver door lock cylinder, turned to the unlock position and held for 3 seconds or longer, or turned to the unlock position twice within 3 seconds. A mechanical linkage rod connects the driver door lock cylinder to the key cylinder unlock switch, which is built into the driver door latch assembly. The key cylinder unlock switch contacts, which are normally open, receive a constant ground via the ground circuit. When the door key is turned to unlock, the switch contacts close and the DDM detects a switched ground. The DDM sends a message via GMLAN serial data to the RCDLR, indicating the key cylinder unlock switch request. The RCDLR is the master of all lock and unlock operations. If the RCDLR determines that the key cylinder switch request is valid and conditions are correct, a message via GMLAN serial data will be sent to the DDM, PDM, and BCM to lock or unlock there respective doors.