Avensis Overvoltage Errors

Sounds nasty. I had similar electrical gremlins in my old Renault Megane. Turned out to be a heavily discharged and defective battery causing all sorts of overvoltage issues. Have you had the battery load tested? A failing battery can cause the alternator to work overtime, leading to overvoltage and subsequent system failures.

Interesting, I hadn't thought about the battery being the culprit. How did you figure out it was the battery on your Megane? Were the symptoms exactly the same?

Indeed, the symptoms mirrored yours almost exactly: a cascade of overvoltage errors and seemingly random system failures. The workshop diagnosed it by first conducting a thorough battery load test, revealing its inability to hold a charge. Subsequently, they investigated the alternator's output, confirming it was functioning correctly once a healthy battery was installed. I suggest you seek professional diagnostic assistance; this could prevent further damage.

Thanks for the tip! Took it to a workshop, and you were spot on. Turns out the battery was heavily discharged and causing the overvoltage. New battery fitted, and all the errors are gone. Cost me 290€ in the end. Appreciate the help!