Door Module - Operation

OPERATION

The microprocessor-based electronic door control modules contain logic circuits that monitor various hard wired, multiplexed and Controller Area Network (CAN) B data bus message external inputs from the power window, power mirror and memory switches on their respective doors. The door control modules also monitor hard wired power window motor and power mirror motor Hall effect sensors as express power window and memory mirror position inputs.

In addition, each door control module receives electronic message inputs from and shares its resources through electronic message outputs to other electronic control modules in the vehicle over the CAN B data bus network. The program logic within the door control module allows the microprocessor to prioritize all of these inputs and determine the tasks it needs to perform. These tasks are then completed either by controlling hard wired outputs to the various motors and lamps contained on its own door or by sending electronic message requests over the CAN bus network to the appropriate electronic module in the vehicle.

The door control modules are powered by a fused accessory delay relay output circuit through a circuit breaker in the Power Distribution Center (PDC) and are grounded at all times so that they can operate for a programmed period of time after the ignition is turned to the OFF position, so long as a door is not opened. The door control modules use On-Board Diagnostics (OBD) and communicate with a diagnostic scan tool using the CAN data bus.

The hard wired inputs and outputs of the door control module may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the door control module electronic controls or the communication between modules and other devices that provide some features of the power window, power mirror, memory, turn signal and courtesy lighting systems. The most reliable, efficient and accurate means to diagnose the door control modules or the electronic controls and communication related to system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.