VW Lupo Audio System Dead: MOST Bus Issue Alert

Speaking from some experience with car electronics, I had a very similar issue with my 2004 VW Polo Diesel. The entire infotainment system showed the same symptoms, power but no function, affecting multiple components simultaneously. After running car diagnostics, the workshop found a defective control unit in the fiber optics MOST bus network. These bus network failures are quite common in vehicles from that era, especially when multiple entertainment components fail at the same time. The repair involved replacing the faulty control unit and testing the entire bus network to ensure proper communication between components. Total cost was around 1000€, including parts and labor. In my case, it was worth fixing rather than replacing the whole system, since a complete system replacement would have been significantly more expensive. To better assist with your specific case, could you share: Have you noticed any other electrical issues? Does the system show any specific error codes? Are there any visible damages to the wiring around the head unit? Did this issue start suddenly or develop gradually? These details would help determine if your issue is similar to what I experienced and whether the same solution might work for you.

Thanks for sharing your experience with the MOST bus repair. My vehicle had its last service at 46000km where they did a full electrical system check that came back clear. The issue appeared suddenly after a particularly cold night, no gradual deterioration or warning signs. The diagnostic scan shows error code 01044 which points to a MOST bus network failure. Visually inspecting the head unit area and wiring shows no obvious damage or loose connections. No other electrical issues present in the car, all other systems like windows, central locking, and climate control work perfectly fine. The head unit display still powers up normally, we just get zero audio output or navigation function. Are these symptoms consistent with the control unit failure you experienced? Wondering if 1000€ is still a reasonable repair estimate for this specific issue today.

The symptoms you describe are nearly identical to what I experienced with my VW Polo. The error code 01044 matches exactly what my diagnostics showed, confirming the MOST bus data transmission issue. The fact that it occurred after a cold night aligns with my experience too. The fiber optics in these systems can become more vulnerable to failure in extreme temperatures, especially in vehicles of this age. In my case, the control unit replacement resolved all issues completely, restoring both audio system function and navigation capabilities. While the 1000€ I paid still reflects current market rates, you might want to have the workshop verify that the fiber optic cables themselves haven't degraded. Sometimes the cables can develop micro-fractures that disrupt signal transmission through the bus network. From the successful repair on my vehicle, I can confirm that once the faulty control unit was replaced and the MOST bus network was properly reconnected, all entertainment functions returned to normal. The repair has lasted without any recurring issues for over two years now. Just ensure the workshop thoroughly tests the entire data transmission pathway after repair, as proper signal flow through the MOST ring is crucial for all components to function correctly.

The symptoms you describe sound very similar to my situation and match typical MOST bus failures. Based on your experience with the repair holding up for 2+ years, I feel more confident about proceeding with fixing the system rather than replacing it entirely. Given that my car diagnostics shows the same error code 01044 and similar behavior after cold exposure, I suspect the control unit needs replacement just like in your case. The consistent 1000€ repair cost helps with budgeting. I will get the workshop to check both the control unit and inspect the fiber optic cables in the bus network, as you suggested. It makes sense to verify the complete signal path since temperature could have affected multiple components in the audio system. Will book it in for repair next week and make sure they do a full test of the entertainment functions after fixing the MOST bus connection. Thanks for sharing your detailed repair experience, it really helped clarify what I'm dealing with and what to expect from the fix.