Dead Sharan Audio & Nav: MOST Bus Failure Help Needed

Faced the same MOST bus failure in my 2007 VW Touran 2.0 TDI. The data transmission between control units completely stopped, causing the audio and navigation screens to go dark. The root cause was a defective fiber optic control unit, not the entire bus network. The main amplifier unit was damaged and no longer communicating with other components in the MOST bus system. This is a serious issue requiring specialized diagnostic equipment. A standard OBD reader cannot properly diagnose MOST bus problems. The repair involved replacing the amplifier control unit and recoding it to work with the existing bus system. The fiber optic ring itself was intact, which saved considerable work. When the MOST bus fails completely, all entertainment and navigation functions stop working, exactly as described in your case. Key is finding a shop with proper diagnostic tools for optical bus systems. Many general mechanics lack the equipment to properly test MOST network components. The repair requires specific knowledge of how the control units communicate through the fiber optic bus network. Based on your symptoms, likely the same amplifier failure. Have it checked by a shop specializing in automotive network systems before replacing parts.

Thanks for sharing your experience with the MOST bus failure. Had the exact same symptoms on my Sharan, complete audio and nav blackout. Got it fixed about 6 months ago. The fiber optics control unit was the culprit in my case too. Thankfully didnt need to replace the entire bus network. The car diagnostics showed it was just the amplifier unit that stopped communicating through the MOST bus. How much did your repair end up costing? And has everything been working properly since the fix? Mine set me back around 850€ including parts and labor, but wondering if prices vary much.

Had to pay 1000€ to get the MOST bus fault resolved in my Touran. The car electronics specialist confirmed the fiber optics control unit was causing the data transmission failure. Since replacing the defective control unit and having it properly coded to the bus network, all systems have been working flawlessly for over a year now. The car diagnostics showed it was definitely the right call to replace just the control unit rather than the complete fiber optic ring. Your repair cost of 850€ seems in line with what these specialized fixes typically run. The key was finding a shop with the proper diagnostic equipment to accurately pinpoint the issue in the MOST bus system. What really matters is that both our entertainment and navigation systems are back to normal operation. These optical bus network failures can be tricky to diagnose, but once properly fixed, they tend to stay fixed.

After reading about your Touran repair cost, I feel better about what I paid. Finally went to a specialist shop after my regular mechanic couldn't diagnose the MOST bus issue properly. They had the right car diagnostics equipment and quickly found the faulty control unit. The data transmission problem was fixed in one day. Total cost was 850€ which included the new control unit, programming, and labor. The automotive protocol coding had to be done precisely to get everything communicating again through the fiber optics. Been running perfectly for 6 months now, all screens working, sound system clear, and navigation spot on. Worth every cent to have it done right by someone who actually understands these complex bus systems. Really wish I had skipped the first mechanic and gone straight to the specialist. Would have saved time and frustration.