DS5 Undervoltage Errors

Hey, that sounds familiar! I had similar issues with my old Opel Astra. By 'undervoltage errors', do you mean you saw a warning light on the dashboard, or the car's computer is showing a fault code when scanned? The battery could be the first thing to check but it could also be something like the voltage regulator or a bad connection. Have you checked the battery terminals for corrosion?

Yeah, the error comes up on the display. I will check the battery terminals. What's a voltage regulator and how do I check it?

Okay, so the display is flagging the error. The voltage regulator is part of the alternator; it controls how much charge goes to the battery. If it's faulty, it can undercharge or overcharge the battery, leading to your symptoms. Honestly, checking it properly needs some equipment, so it might be best to take it to a workshop for them to diagnose. Could save you some time and money in the long run.

Thanks, I appreciate the help. Took it to a shop, and you were right - the battery was gone. New battery installed and all errors are gone. Cost me 290€.