VW Golf Multiple Electronic Failures Due to MOST Bus

Had exactly this issue with my 2013 VW Passat Hybrid. With some experience working on car electronics, I initially thought it was just the audio unit acting up, but it turned out to be more complex. The symptoms matched yours perfectly, complete audio failure, navigation dead, multiple error codes. The workshop diagnosed a defect in one of the control units connected to the automotive protocol system, specifically the MOST bus network. The fiber optic data transmission ring was interrupted due to a faulty control module. The repair involved: Complete diagnostic scan of the bus system, Testing all control units in the network, Replacing the defective control module, Reprogramming the new unit, Testing all car electronics to ensure proper communication Total cost was 1000€ including parts and labor. The car has worked flawlessly since the repair. To help more specifically with your case: Which error codes are you seeing? Have you noticed any other electrical issues? Does the problem occur immediately after starting or develop while driving? Are all displays affected or only certain systems? These details would help determine if your issue is identical to what I experienced with the bus network failure.

Latest service was at 52000km, and currently showing 54930km on the odometer. The fault codes I am seeing are: U1000, Communication fault U0100, Lost Communication with ECM/PCM A U0164, Lost Communication with HVAC Control Module U0028, Vehicle Communication Bus A Off The issues appear immediately after starting the car and stay consistent. All displays remain functional, but the entire infotainment and audio system is completely dead. No other electrical problems noticed so far. A basic car diagnostics scan confirms multiple communication errors across the system. The symptoms match exactly what you described with the MOST bus network issue. Given the repair cost estimate, I will schedule an appointment with a workshop specializing in automotive protocol systems rather than the regular dealership. Thanks for the detailed breakdown of the repair process, this helps set the right expectations.

Thanks for providing those specific fault codes, they are exactly what I encountered with my Passat before the repair. The U1000 and U0028 codes especially are classic indicators of a MOST bus fault, usually pointing to a break in the fiber optics ring. My car actually showed the same mileage range when the issue occurred (around 55000km), which seems to be a common point for these fiber optics failures in our model series. Quick tip from my experience: Make sure the workshop performs a complete car diagnostics sweep before replacing any components. In my case, they initially wanted to replace the audio system head unit until a thorough control unit scan revealed the actual MOST bus communication issue. After going through the repair process, I learned that the fiber optic ring needs to be completely intact for the system to work, even a tiny break in one connection point can cause all these symptoms. The workshop should check each control unit in the chain to identify the exact failure point. Would definitely recommend having this fixed soon, driving without proper system communication can potentially lead to other control unit issues down the line. The 1000€ I paid ended up being worth it for the long-term reliability.

Based on these details and your experience, I will proceed with booking the specialized workshop. Your situation has helped confirm my suspicions about the MOST bus network being the root cause, especially given the matching fault codes and similar mileage point where the issue occurred. I performed one more car diagnostics scan this morning to document any additional codes, but the results remain consistent with what I shared earlier: U1000, U0100, U0164, and U0028. All pointing to communication and bus system failures. The control unit errors and complete audio system shutdown match the pattern exactly. Good advice about having them do a complete diagnostic sweep, I will specifically request this to avoid unnecessary parts replacement. Will schedule the repair next week and expect around 1000€ for the fix based on your experience. Having a functioning infotainment system and properly communicating control units is worth the investment. Thanks for helping confirm the diagnosis and sharing the detailed repair process. This saved me time troubleshooting and helped narrow down the exact issue.