Tech Tips (by ALLDATA): Volkswagen Jetta has ‘no-start issue’ after battery jumped
TECH TIPS (courtesy of ALLDATA)
Problem: Vehicle was towed in to the shop for a no-start condition ever since the vehicle was jump-started from another vehicle. According to the vehicle owner, the battery was not jumped backwards. There was no flash and no arching marks visible on the battery terminals.
Details: The technician retrieved 35 diagnostic trouble codes (DTCs) of all different types from many different modules. There was also a burned smell in the vehicle.
The tech noticed that the gauges and lights in the instrument cluster would not work with the key in the “On” position. Since the “wake-up” signal for the instrument cluster comes from the body control module (BCM) through the data line, he decided to check the BCM first. After verifying that power and grounds to the BCM were all were within specifications, he opened the BCM cover.
Confirmed Repair: Under the cover, the problem was clear. The circuit board was badly burned. The technician reprogrammed a used BCM as a replacement. The issue was resolved.