GMC Terrain's Dead Infotainment Points to MOST Bus Issue

Had the same data transmission issues on my 2017 GMC Acadia last winter. The MOST bus system failure caused complete audio system blackout and navigation malfunction, matching your symptoms exactly. The diagnostic revealed a defective fiber optic ring, which is a critical part of the automotive protocol network connecting multiple control units. The main issue was a break in the optical cable near the amplifier module. This is considered a serious electrical fault because the MOST bus handles all infotainment communications. When one component fails, it can interrupt the entire chain of car electronics. The repair required: Complete diagnostic of the MOST network, Replacement of the damaged fiber optic section, Reprogramming of affected control modules, System initialization and testing The fix took 3 days at the shop due to the complexity of working with fiber optics. Its essential to have this repaired by technicians with specific experience in automotive bus systems, as incorrect repairs can damage other connected modules. Based on your description, you likely have a similar fundamental issue in the MOST network rather than just a single component failure.

Thanks for sharing your repair experience. I actually had the same car diagnostics nightmare with my 2019 Terrain. Your description of the fiber optics failure matches what my mechanic found. Did the repair completely solve the issue for you? Would you mind sharing what you paid for the fix? Its been about 6 months since my repair and fortunately no other data transmission problems have surfaced, but Im curious if you encountered any related issues afterward.

After getting the repair done, my GMC Acadia has been working perfectly with no further data transmission problems. The repair cost was 1000 Euro to fix a faulty control unit that was disrupting the MOST bus network. Once the technician replaced the defective component, all the infotainment functions were immediately restored. The audio system and navigation are now functioning as they should. The key was finding a shop with expertise in car electronics and MOST bus diagnostics. They identified the specific control unit causing the network interruption rather than just replacing parts out of nowhere. The thorough diagnostic approach they used prevented any recurring issues. Six months later, the bus network remains stable with no transmission errors. The investment in proper repair was worth it to restore full functionality to the infotainment system.

Thanks everyone for the helpful feedback. I finally took my Terrain to a specialized shop last week. The mechanic found a damaged fiber optic cable in the MOST bus network, exactly as described. The control unit connecting to the audio system was also malfunctioning. Total repair cost came to 1200 Euro including diagnostics and labor. They had to order specific parts which took 2 days, but the actual repair only needed one day. The automotive protocol system is now working perfectly, all infotainment functions, navigation and audio system are back to normal. The car electronics specialist explained everything clearly and showed me the damaged components. Much better experience than my previous repair attempts elsewhere. Really glad I found a shop that actually understands these complex bus systems rather than just guessing at the problem.