Power Lock System
The power lock system uses non-switched battery current received through a fused B(+) fuse in the Body Control Module (BCM) (also known as the Common Body Controller/CBC) so that the system remains operational regardless of the ignition switch position. The BCM is the primary power lock system controller. The power lock switches are hard wired to their respective Driver Door Module (DDM) or Passenger Door Module (PDM). The BCM, the DDM and the PDM all communicate with each other and with other electronic modules in the vehicle over the Controller Area Network (CAN) data bus.
When a door module receives an input from a power lock switch, it sends the appropriate electronic Lock Request or Unlock Request message to the BCM over the CAN data bus. The BCM responds to these request messages by providing the appropriate outputs to each of the power lock motors to lock or unlock each of the door latches. The BCM also monitors a hard wired input from the deck lid release switch and electronic message inputs indicating automatic transmission gear selector position and vehicle speed. The BCM uses all of these inputs and internal programming to determine whether or not to provide the output necessary to operate the deck lid latch release motor.
The BCM also stores the power lock system Customer Programmable feature settings received over the CAN data bus from the Electronic Vehicle Information Center (EVIC). The BCM uses these settings and internal programming along with hard wired 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 the microprocessor and software contained within the BCM, the DDM and the PDM. When one of these modules 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 hard wired 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 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.