Body Control Module (BCM)

The power lock system uses non-switched battery current received through a fused B(+) fuse in the BCM so that the system remains operational regardless of the ignition switch position. The BCM is the primary power lock system controller.

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-IHS 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 tail gate 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 liftgate latch release motor.

The BCM also stores the power lock system Customer Programmable feature settings received over the CAN data bus from the IPC. 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 BCM. When the BCM monitors a problem in any of the power lock system circuits or components, it stores a fault code or DTC in its memory circuit.

RKE Specific:

In the event that the vehicle is not equipped with PEKG, the RFH module receives data signals from the key fob. These data signals can include the number of button presses and which button was pressed to determine the requested event. The RFH sends the request to the BCM which then reads this data to provide the appropriate hard wired outputs to invoke the proper RKE system features and responses.

If these data signals indicate that the doors are to be remotely locked, the BCM sends the output for a single horn activation and turn signal lamps illumination when vehicle locking is complete.

Also, on vehicle remote start requests, the BCM performs a central locking command upon successful engine starting.

Inputs

• The BCM receives an input from the ajar switches to wake the module as well as the state of the VAP
• Accelerator position from the PCM for auto lock and unlock feature
• Door lock cylinder switch inputs to the BCM when a key is inserted
• Lock and unlock inputs requests from the RFH
• Customer programmable features from the radio
• Key fob authentication from the RFH
• Anti-lock Brake System (ABS) module vehicle speed signal
• PE enable signal from the RFH

Outputs

• Managed and control the outputs to the power lock system and relays
• Turn signal lamp activation
• Horn activation
• Output to the IPC for illumination and indication messages
• Panic alarm active signal
• Authentication confirmation for PE and key fob to the RFH