Power Lock System
The power lock system uses non-switched battery current received through a B(+) fuse so that the system remains operational regardless of the ignition switch position. The BCM is the primary power lock system controller. The power lock switch (also known as the door inhibit switch) is hardwired to the BCM.
When the BCM receives an input from the power lock switch, it provides the appropriate hardwired output to energize or de-energize the power lock relays soldered onto its printed circuit board. The relays control the flow of battery current and ground to each of the power lock motors to lock or unlock each of the doors.
The BCM also stores the power lock system Customer Programmable feature settings received from the Electronic Vehicle Information Center (EVIC) circuitry of the Instrument Panel Cluster (IPC). The BCM uses these settings and internal programming along with hardwired and electronic message inputs to determine the proper outputs needed to produce each of the appropriate power lock system features.
The power lock system circuits are continually monitored and controlled by a microcontroller and software contained within the BCM. When the BCM monitors a problem in any of the power lock system circuits or components, it stores a fault code or Diagnostic Trouble Code (DTC) in its memory circuit. The hardwired circuits between components related to the power lock system may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds.
However, conventional diagnostic methods will not prove conclusive in the diagnosis of the power lock system or the electronic controls or communication between other modules and devices that provide some features of the power lock system. The most reliable, efficient, and accurate means to diagnose the power lock system or the electronic controls and communication related to power lock system operation, as well as the retrieval or erasure of a DTC requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.