Power Lock System
The power lock system uses non-switched battery current received through a fused B(+) fuse in the Body Control Module (BCM) 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), Passenger Door Module (PDM) or Power Sliding Door Module (PSDM). 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.
OPERATION
- 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 liftgate release switch and the power sliding door 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 liftgate or sliding door 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 microcontroller 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.