Peugeot 5008 Overvoltage Errors

Sounds familiar! I've got a 5008 too, and chased similar symptoms for weeks. Constant overvoltage codes will drive you nuts. Have you checked the battery's resting voltage? And looked at the alternator output with a multimeter when the engine's running? Gotta rule out those basics first.

Yep, I checked the battery, it was heavily discharged which led me to think it's a defective battery. But I'm not sure what normal values should be for voltage? Could this really cause this many seemingly unrelated problems?

Believe me, a bad battery or a dodgy alternator can throw Peugeot electronics into a frenzy. All those systems are interconnected. If the battery's weak, the alternator strains to compensate, potentially causing voltage spikes. I'd get the battery properly load tested, and if it is indeed defective, replace it immediately. If that doesn't resolve it, you're likely looking at an alternator failure. Might be time to bite the bullet and take it to a workshop if you don't have experience with these things.

Thanks for the insight! I replaced the battery as you suggested, but the issue remained. Ended up taking it to the shop. Turns out you were right, the alternator was the culprit. Cost me 290€ for the repair, but everything's back to normal now. Appreciate the help!