Viano Fault Memory Lock Active Error

Has anyone seen this before? My 2006 Mercedes Viano with a diesel engine and 275399 km is throwing a "Fault memory lock active" error. The error is stored in the error memory. ECU diagnostics points to undervoltage. What gives?

4 comment(s)

Sounds familiar. I had a similar issue with my Vito, although I can't recall the exact fault codes. It was something to do with the car electronics and the control unit losing power intermittently. Have you checked your battery and alternator?

Yeah, battery seems fine. Alternator too, as far as I can tell. When you say 'similar issue', was it also triggering the 'Fault memory lock active' message during your automotive diagnostics?

Correct, that's the one. From what I remember, it kept logging errors, and the diagnostics kept pointing to undervoltage issues. After a bit of back and forth I ended up taking it to a workshop. They sorted it out in a couple of hours. Best of luck.

Cheers. Workshop visit it is then. It ended up costing 240€ but they fixed the issue.

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