PT Cruiser MOST Bus Failure Hits Audio & Navigation

As someone with moderate experience in car electronics, I encountered a similar issue with a Chrysler Sebring diesel from 2004. The symptoms were nearly identical, complete audio failure and navigation problems tied to MOST bus data transmission issues. The car diagnostics revealed multiple control unit communication errors. After visiting three workshops, we finally found one specializing in automotive protocol systems. They identified a defective fiber optic ring controller in the main control unit, which was disrupting the entire MOST bus network. The repair process involved: 1. Complete system diagnostic scan 2. Testing individual control unit connections 3. Replacing the faulty control module 4. Reprogramming the new unit 5. System-wide testing to ensure proper data transmission Total repair cost was 1000€ and took about 4 days to complete due to parts ordering and extensive testing requirements. Before suggesting specific solutions for your PT Cruiser, could you share: Current mileage, Any recent electrical work or installations, Whether the problem appeared suddenly or gradually, If any warning lights are active on the dashboard, Results from any previous diagnostic attempts This information would help determine if your issue matches the common MOST bus failure pattern I experienced.

Thanks for sharing that detailed experience with the Sebring. My issue started gradually over about 2 weeks. Just had my regular service done last month at 109873 KM. No warning lights are active and no recent electrical work was performed. The diagnostic attempts so far only confirmed the MOST bus network errors, but didnt pinpoint the exact location of the failure in the data transmission system. Your control unit repair path sounds promising, will get that checked specifically. Were there any other symptoms in your case before the complete audio system failure?

Thanks for those additional details. On my Sebring, there were actually a few early warning signs before the complete audio system failure that match what you might be experiencing: The first symptoms included: Unusual audio dropouts lasting a few seconds, Navigation screen occasionally freezing, Audio system taking longer than usual to initialize after starting the car The gradual onset you mentioned over 2 weeks closely mirrors my experience with the MOST bus failure. The clean service history and lack of warning lights also matches my case, which made initial diagnosis tricky for several mechanics unfamiliar with car electronics and bus network issues. Since your diagnostic results show similar MOST bus system errors, I strongly suspect the same fiber optic ring controller issue. The repair costs might be slightly different for the PT Cruiser, but the diagnostic approach should be identical. One tip: When I had the work done, I insisted they perform a complete bus network signal strength test before and after the repair. This extra step helped confirm the fix was successful and prevented any follow-up issues with the audio system. Would you mind sharing if you notice any pattern to when the audio failures occur? For example, do they happen more frequently when the car is cold or after driving for a while?

Now let me ask about those specific timing patterns of the failures you mentioned. In my case, the issues definitely happen more when the car is cold, especially during morning starts. After about 15-20 minutes of driving, the audio system seems to work better, though still not perfectly. The navigation freezes are completely unusual though. Good tip about requesting the signal strength test, will definitely ask for that. The gradual deterioration you described matches my situation exactly, particularly those audio dropouts and delayed system initialization. Going to schedule an appointment with a workshop that specifically handles fiber optics and MOST bus diagnostics. If the control unit needs replacement, I hope the parts are still available for my 2002 model. Let me know if you encountered any reliability issues with the new control unit after your repair was completed. Really hoping this fixes both the audio and navigation problems without requiring additional work on other components of the bus network.