Peugeot 407 Fault Memory Lock Active

That "Fault memory lock active" message on your 407 could be a few things, but it often points to undervoltage issues messing with the computer system. Has the car been sitting for a while, or have you had any battery problems recently? Did you check all fuses? What does your OBD2 reader say about the exact error code?

Thanks for the quick reply! The car gets driven regularly, so it's not sitting. I haven't noticed any battery issues either, it starts fine every time. I didn't check the fuses. What fuses should I be looking at specifically? The cheap OBD2 reader only shows the 'Fault memory lock active' message, nothing more specific.

Okay, since the battery seems fine and the car is used often, the undervoltage might be transient or related to a specific component pulling too much power. Without a proper diagnostic tool, pinpointing it will be tricky. Check the fuses related to the ECU and engine management system according to your owner's manual. However, given the 'memory lock' aspect, it really does sound like the ECU is having issues. Honestly, I'd recommend taking it to a workshop with proper Peugeot diagnostic equipment to avoid causing further problems. It's tough to diagnose remotely, and you might end up chasing ghosts.

Alright, thanks for the advice. I suspected it was something beyond my capabilities. Took it to the shop and they said it was undervoltage related to a faulty control unit. Repair cost was 240€. Ouch! But at least it's fixed.