Mercedes GLS fault memory lock issue

Whoa, that sounds frustrating! I have a GLS too, and I had a similar issue pop up a while back. Active memory problems are the worst. Did you try clearing the error codes to see if it comes back? Mine was doing something similar and I was pulling my hair out trying to figure out what was going on. It ended up being a pain.

Yeah, I tried clearing the codes, but the "fault memory lock active" prevents that. Did you ever figure out exactly what triggered yours? And how did you eventually get rid of it? I'm trying to avoid a huge auto repair bill if possible.

Okay, if the memory lock is active, that's a different story than what I initially thought. Mine cleared right away, so that wasn't the same. Honestly, with the memory lock, I'd suggest taking it to a reputable workshop with good automotive diagnostics equipment. It could be something deeper, and you don't want to mess with the ECU yourself. Might be a quick fix for them.

Thanks for the advice. I ended up taking it to a shop, and you were right – the fault memory lock active made it a bit more complicated. Turns out it was a voltage issue, like I suspected. They cleared the codes and checked the system and it all seems fine now. Cost me 240€, so not too bad in the end.