The following Volkswagen technician tip comes courtesy of Mitchell 1’s SureTrack Real Fix blog
Vehicle: 2002 Volkswagen New Beetle GLS, 1.8-L
Complaint: The customer states the left front power windows, power door locks, and power mirrors are inoperative.
The customer’s complaint was confirmed — the left-front power window was inoperative. A scan tool was connected and found codes: 01331 – Door Control Module; Driver Side (J386): Supply Voltage Too Low and 01336 – Data Bus for Comfort System: Faulty.
The next step was then to remove the left-front door panel and perform a visual inspection of the power window motor. There were no obvious faults found.
Next, the door control module connector was disconnected and the connector pins and terminals were visually inspected — no faults found.
A multimeter connected to the door control module measured the voltage and verified that power and ground were present at the door control module. A lab scope connected to the door control module measured voltage, while activating the power window switch in both the up and down directions, and found that the signals were present at the door control module.
The lab scope was moved to test leads to the communication high and low terminals at the door control module, and both signals were monitored simultaneously. Both were present.
The result of these tests verified that the door control module was faulty. The door control module is integrated into the left-front power window motor, and is replaced as an entire unit.
Correction: Replaced the left-front power window motor, cleared codes, performed a road test and verified the vehicle operated properly.
