Peugeot 406 Automatic Transmission Issue

Sounds familiar! I had a similar issue with my 406. The shifting became erratic, and the transmission light lit up like a Christmas tree. For me, it turned out to be undervoltage in the vehicle messing with the transmission's brain. Have you checked your battery and alternator? Think of it like a dimmer switch slowly fading the lights – not enough juice for the tranny to operate smoothly.

Interesting idea about the undervoltage. I hadn't considered that. So, did fixing the voltage issue completely resolve your transmission problems, or did you have to do anything else?

Yeah, in my case, sorting out the electrical gremlins did the trick. But honestly, with those symptoms, it's worth getting it checked out by a professional. It could be a more serious transmission issue. Think of it like a leaky faucet; sometimes it's just a loose washer, but other times it's a whole pipe that needs replacing. I'd suggest taking it to a workshop to be safe.

Thanks for the advice! I took it to a shop, and you were right – it was undervoltage! They sorted out the wiring, and it's shifting smoothly again. The total repair bill was 240€.