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Last week suffered a driver's side front Door Control Module (DCM) and Lower Control Panel (LCP) failure. Passenger side front DCM continued to work to adjust the seat but that was all.
This time I didn't even bother to connect the diagnostic system (although that is recommended) or check fuses. I removed the X30/7 connector from the passenger side front trough, inserted my test connector, and connected the multimeter.
Expected voltages: CAN L: dormant 4.8 volts, active 3.2 volts
CAN H: dormant 0.2 volts, active 1.8 volts Actual voltages: CAN L: dormant: 4.89 volts, active 4.72 volts (note: 4.89 is normal for this car)
CAN H: dormant 0.17 volts, active 0.17 volts
Began pulling and reinserting connectors one at a time. #10 (PSE vacuum pump), no change. #9 (passenger side R.R. window control module), voltages stabilized and driver's DCM and the LCP regained functionality. Pulled the door panel, disconnected the window control module from the harness, reinserted the #9 connector into the junction block, and voltages remained stable. Bad passenger side rear window control module it is.
That module is no longer available new; I located one on Ebay and purchased it. I also purchased another used spare plus a new OEM driver's side rear window control module. I intend to disassemble the faulty module and see if I can repair it. Unknown but worth a shot as parts are getting more difficult to locate for these cars.
See the attached .pdf for a summary of the W210 CAN Bus info.
Photo of culprit here:
Last edited by bbirdwell; Apr 21, 2024 at 04:09 PM.
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