Talisman Electrical Gremlin Overvoltage Errors

I had a similar problem with my Talisman a while back. Lots of seemingly unrelated systems failing, accompanied by overvoltage warnings. It's like the car's electrical system is a dam that's about to burst. Have you checked the battery's condition thoroughly? A heavily discharged or even a defective battery can cause all sorts of havoc with modern car electronics due to voltage regulation issues. What kind of voltage readings are you getting when the engine is running?

Thanks for the quick reply! I haven't checked the voltage while the engine is running, but I did test the battery when the car was off, and it seemed a bit low, around 12.2V. Could a slightly weak battery really cause so many different system failures? It seems crazy that a single component could bring down half the car!

12.2V is definitely on the low side, especially for a modern car packed with electronics. And yes, a weak battery can absolutely cause a cascade of failures due to the sensitive nature of the car's electrical system. The overvoltage errors are likely a symptom, not the root cause. Given the symptoms and the mileage, I strongly suggest getting the battery professionally tested and replaced if necessary. It might save you a lot of headache chasing phantom issues. You may want to consider visiting a workshop, they will be able to measure the battery's internal resistance.

You were spot on! I took it to a workshop, and it turned out the battery was indeed heavily discharged and defective. Replaced it for 290€, and all the errors are gone. Everything is working perfectly now! Thanks a million for pointing me in the right direction. I was fearing the worst, like some major wiring harness issue or a faulty ECU. Lesson learned: don't underestimate the humble battery!