After accidentally shorting the fuse box live wire to the car body during an amplifier installation, the MMI stopped working and a “parking brake malfunction” appeared on the DIS display. Using VCDS Release 17.1.3, a scan revealed several fault codes related to the parking brake and an inability to communicate with the MMI system components.
Diagnosing the Parking Brake with VCDS 17.1.3
The VCDS scan, using version 17.1.3, provided the following error codes for the parking brake system:
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00576 – Terminal 15: This code indicates an electrical fault in Circuit 15, a critical circuit that powers many essential components. The “MIL ON” status signifies that the malfunction indicator lamp (check engine light) is illuminated. Freeze frame data shows the fault occurred at 15:50:06 on July 18, 2017, with a system voltage of 11.70V.
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02434 – Supply Voltage for Control Module for Left Channel: This code suggests an issue with the power supply to the left channel of the parking brake control module. “Open or Short to Ground” points to a potential wiring problem, either a broken wire or a short circuit to ground. The freeze frame data records a voltage of 12.21V.
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02435 – Supply Voltage for Control Module for Right Channel: Mirroring the previous code, this indicates a similar problem with the right channel of the parking brake control module. The recorded voltage is 12.32V. Both 02434 and 02435 have a “MIL ON” status, indicating their severity.
These codes, logged by VCDS release 17.1.3, suggest a potential power supply issue to the parking brake control module, possibly caused by the short circuit. Clearing the codes with VCDS didn’t resolve the issue, indicating a persistent hardware problem.
MMI Communication Failure
In addition to the parking brake faults, VCDS release 17.1.3 was unable to establish communication with any MMI components. This suggests that the short circuit may have damaged the MMI system or a related communication bus. All fuses were checked and found to be intact, ruling out a simple blown fuse as the cause.
Next Steps
The next steps involve a more thorough inspection of the wiring and components related to both the parking brake and the MMI systems. This includes checking for damaged wires, loose connections, and potential damage to control modules. Using a multimeter to test voltage and continuity in relevant circuits can help pinpoint the source of the problem. Given the complexity of these systems, consulting a qualified automotive electrician or using VCDS 17.1.3 in conjunction with factory wiring diagrams is recommended for further diagnosis and repair. The initial short circuit likely caused more extensive damage than initially apparent, requiring a systematic approach to troubleshooting.
