Buick Audio Dead: MOST Bus Failure Symptoms & Fixes

I had a similar issue with my 2006 Buick Park Avenue. With some experience working on car electronics, I initially tried basic troubleshooting but quickly realized this was beyond standard DIY fixes. The symptoms matched yours exactly, complete failure of the audio system and navigation. The fiber optics in the MOST bus network were compromised, causing data transmission issues between control units. After diagnostic testing, the workshop found a defective control unit that was disrupting the entire bus network. The repair involved: Full system diagnostic scan, Replacement of the faulty control unit, Reprogramming the new unit, Testing all connected systems Total cost was 1000 Euro for parts and labor. The repair took about 6 hours since they had to verify the entire data network was functioning properly after the replacement. To better assist with your specific case, could you share: Any error codes stored in the system? When did the issue start? Sudden or gradual failure? Have you had any recent work done on the audio system or electrical components? Does the system show any signs of life at all (lights, partial function)? This information would help determine if your issue is similar to what I experienced or if it might be something else affecting the MOST network.

At 130629 KM and having just completed my service last month, I finally resolved my audio system issues. You hit the nail on the head about the MOST bus system. My car diagnostics revealed similar symptoms with the fiber optics network completely failing. After extensive testing, the control unit was indeed the culprit. The repair involved a complete replacement of the main entertainment module and recalibration of the system. The car electronics are now functioning perfectly, radio, navigation, and all audio components are back to normal. Worth noting that during diagnosis they found the original fiber optic cables were also degraded, likely due to age. Getting those replaced at the same time was a smart preventive measure to avoid future system failures. Total repair time was around 4 hours. The system needed full reprogramming after component replacement, but it was worth the wait for a properly functioning entertainment system.

Thanks for the update on your repair experience. Good to hear you got it sorted, and even better that my diagnosis about the MOST bus matched your actual issue. Having gone through this myself, I know how frustrating these audio system failures can be. Smart move getting those fiber optics replaced while they were in there. The preventive replacement often saves headaches later since degraded cables can cause intermittent control unit issues that are harder to diagnose. The repair cost and time on yours was a bit better than mine, probably because they could pinpoint the issue faster with the clearer symptoms. When my car electronics started acting up, it took longer to isolate the specific control unit causing the problem. One heads up from my experience, keep an eye on the system over the next few weeks. Sometimes after a major repair like this, the car electronics might need minor adjustments as everything settles in. If you notice any quirks with the audio system, get it checked while its still under repair warranty. The 4-hour turnaround for a complete control unit replacement and reprogramming is pretty standard when dealing with MOST bus repairs. Glad to hear everything is working as it should now.

Thank you for helping confirm the MOST bus system diagnosis. The car diagnostics matched exactly what you described, it was definitely the control unit failure affecting the entire network. Your advice about replacing the fiber optics cables was spot on. The technician explained how the bus network degradation had been gradual, and replacing both the cables and control unit was the right call. The audio system is now working flawlessly. The 4-hour repair time was reasonable considering they had to do complete reprogramming. I will monitor the car electronics over the next few weeks as suggested. The shop explained that the new control unit might need fine-tuning as the system fully integrates. I appreciate the help in diagnosing this, it saved time by going straight to the core issue rather than trying partial fixes. For anyone else facing similar symptoms, having a proper diagnostic scan done is crucial before attempting any repairs to the bus network. Final repair costs were in line with what you experienced, though I saved some labor time since they identified the problem quickly. Money well spent to have a fully functioning entertainment system again.