Door Control Module
DESCRIPTION
This vehicle is equipped with two Door Control Modules (DCMs):
- Drivers Door Module (DDM) (1)
- Passenger Door Module (PDM) (2)
Each DCM contains a Central Processor Unit (CPU) and communicates with the other DCM as well as other Electronic Control Units (ECUs) in the vehicle over the Controller Area Network-Interior High Speed (CAN-IHS) data bus system. The DCMs are connected to the vehicle electrical system through connector receptacles that are integral to the module housing.
Each DCM is concealed behind the front trim panel where it is secured through mounting tabs to the door hardware module carrier by fasteners. The DCMs are located in the front door hardware carriers, between the power window motor and the door speaker.
A DCM cannot be adjusted or repaired and, if damaged or ineffective, it must be replaced. The DCM software is flash programmable.
OPERATION
The DCMs contain logic circuits that monitor various hardwired low current, multiplexed and Local Interface Network (LIN) data bus message external inputs from the power window, power lock, power mirror, power sliding door and memory switches on their respective doors. The front DCMs also monitor hardwired power window motor Hall effect sensors and memory mirror position sensor inputs. Other vehicle features that use the DCM include the Blind Spot Monitoring (BSM) system, interior lighting system for switch backlighting commands control and the Heating, Ventilation and Air Conditioning (HVAC) system to perform mirror defogging.
As mentioned, each DCM receives electronic message inputs from and shares its resources through electronic message outputs to other ECUs in the vehicle over the CAN-IHS data bus network. The program logic within the DCM allows the controller to prioritize all of these inputs and determine the tasks it needs to perform. These tasks are then completed either by controlling hardwired outputs to the various motor, actuators, lamps or displays contained on its own door or by sending electronic message requests over the CAN-IHS bus to the appropriate ECUs in the vehicle.
The DCMs are powered by a fused B(+) circuit and are grounded at all times so that they can operate regardless of the ignition position. The DCMs use On-Board Diagnostics (OBD) and communicate with a diagnostic scan tool using the CAN data bus.