klauseagle41

SM3 Audio and Navigation Failure

I've got a 2002 Renault SM3 with a gasoline engine and I'm running into a weird issue. My audio system is completely dead – no sound at all. The navigation is also kaput. Hooked it up to a diagnostic tool and it's showing a MOST bus fault stored in the error memory. Mileage is at 63997 km. Anyone seen anything like this before? Thinking it might be a dodgy control unit on the MOST bus but not sure where to even start looking.

4 comment(s)

Whoa, that sounds familiar! I had a similar problem with my SM3 – though thankfully a bit later model. My radio just went silent one day, and the nav screen froze. After a bit of digging, I figured out it was something to do with that fiber optic cable system they use for the audio. Does the error code point to a specific module, or just a general MOST bus issue? It could be anything from the amp to the head unit, or even the CD changer if you have one.

Thanks for the quick reply! The error code is pretty generic, just says 'MOST bus fault'. Doesn't point to any specific module. How did you eventually resolve your issue? And did you manage to pinpoint which component was causing the problem?

Right, a generic MOST bus fault is a pain. Honestly, I tried poking around myself for a bit, checking connections and stuff, but I eventually threw in the towel and took it to a workshop. Turned out to be a faulty amplifier. Cost me around 1000€ to get it sorted. My advice? Unless you're really comfortable with car electronics, especially fiber optics, get it checked out by a professional. It can save you a lot of headache in the long run.

Appreciate the honest advice. Sounds like I'm in for a trip to the workshop. Guess I'll skip trying to figure out the MOST bus myself and leave it to the pros. Thanks again for sharing your experience!

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