Vios MOST Bus Fault

I'm having a weird issue with my 2007 Toyota Vios. It's got a gasoline engine and about 194000 km on the clock. Suddenly, the audio system is completely dead. No sound, the head unit doesn't seem to work at all, and even the navigation is out. I plugged in a code reader and it's showing a 'MOST bus fault'. Anyone ever run into this? I've checked fuses but can't find anything obvious.

4 comment(s)

MOST bus fault, huh? Sounds like a fiber optic issue. I had something similar in my old BMW, also fiber optics. Could be a faulty control unit on that MOST bus, like the amplifier, radio, or nav unit itself. Is the error always present, or does it come and go?

Thanks for the quick reply! It's always present, unfortunately. What exactly does a faulty control unit do to cause this? And how would I even go about figuring out which one it is?

Okay, 'always present' is less good, points to a hardware failure. A faulty control unit basically breaks the data loop in the MOST bus, like a broken wire in a regular circuit. The signal can't get through. Honestly, without specialized tools, it's tough to pinpoint the exact unit. You might need a proper diagnostic at a workshop. Prepare for some car electronics diagnostics...

Appreciate the help. Sounds like I'm in over my head with the diagnostics. I'll take it to my local mechanic. From what they are saying I should expect around 1000€ for the repair. Thanks again!

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