Seat Leon electrical issues

Sounds like a familiar problem. I had similar high voltage issues with my old Volvo a few years back. The car electronics were going haywire, and I was getting all sorts of fault codes. Did you check the car battery's voltage and charging rate? A failing alternator can also cause overvoltage, but a discharged battery is more common.

Thanks for the quick response. I haven't checked the charging rate yet, but I did test the battery voltage, and it seemed a bit low. How did you pinpoint the car battery as the issue on your Volvo? Was it just trial and error, or did you use some specific diagnostic tools?

In my case, the Volvo was showing similar symptoms – random electrical glitches, error messages, and difficulty starting. I initially suspected the alternator, but after further investigation, it turned out the car battery was the culprit. The internal resistance was too high, causing voltage fluctuations. Given your weak battery and the overvoltage errors, I'd strongly suggest getting the car battery professionally tested or replaced. It's the most likely cause, and it's better to rule it out before chasing more complex electrical issues. A workshop can confirm the issue quickly.

Just wanted to let you know, I took the Leon to the workshop, and you were right. The battery was heavily discharged and defective, causing the overvoltage errors. Replacing it fixed all the electrical issues. Cost me 290€, but it's worth it to have everything working properly. Thanks for the help!