Hilux Overvoltage Errors

That sounds rough! Overvoltage issues can be tricky. Have you checked the battery itself? A heavily discharged or defective battery can sometimes cause weird voltage fluctuations that the system interprets as overvoltage. Also, might be worth having the voltage regulator on the alternator checked out. If it's faulty, it could be pushing too much voltage into the system and frying everything. What kind of condition is your battery in? How old is it?

Good call on the battery and regulator. The battery is maybe 3 years old. I haven't load tested it myself, I just noticed it's been a bit sluggish lately. How would I go about checking the voltage regulator? Is that something I can do with a multimeter, or is it more complicated?

Yeah, 3 years is getting to be the age where batteries can start to cause problems. As for the voltage regulator, you can check the output voltage with a multimeter while the engine is running, but honestly, it's not always conclusive. Plus, with all those other systems going haywire, you could be chasing ghosts. Given the widespread electrical issues, I'd strongly suggest taking it to a trusted mechanic who specializes in automotive electronics. They'll have the right tools and diagnostic equipment to pinpoint the source of the overvoltage and prevent further damage.

Appreciate the advice! You're right, probably best to leave it to the pros before I make things worse. Dropped it off at the shop this morning. Turns out it WAS the battery. Apparently it had an internal short and was causing all sorts of chaos. New battery and a system reset set me back 290€, but at least it's fixed! Thanks again for pointing me in the right direction.