Door Module - Operation

OPERATION

The microprocessor-based electronic front door control modules (also known as a Driver Door Module/DDM, a Passenger Door Module/PDM or Front Door Multiplex/MUX Modules) contain logic circuits that monitor various hard wired analog and low current, multiplexed inputs from the door ajar, power window, power lock and power mirror switches on their respective doors. They also receive Controller Area Network (CAN) B data bus electronic message-based external inputs from the opposing front door control module as well as from other electronic modules in the vehicle. The front door control modules also monitor hard wired power window motor Hall effect sensor inputs.

The program logic within the front 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, actuators or lamps on its own or the rear doors, or by sending electronic message requests over the CAN-B bus to the appropriate electronic module in the vehicle.

The front door control modules are powered by a fused B(+) circuit and are grounded at all times so that they can operate regardless of the ignition switch position. Both driver and passenger door control modules provide active and stored Diagnostic Trouble Codes (DTC) through On-Board Diagnostics (OBD) and communicate with a diagnostic scan tool using the CAN data bus.

The hard wired inputs and outputs of the front 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 electronic controls and communication between modules and other devices that provide some features of the power window, power lock or interior lighting system features the front door control modules provide. The most reliable, efficient and accurate means to diagnose the front door control modules or the electronic controls and communication related to operation of these systems requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.