Peugeot 307 starting issue

That sounds familiar! Had a similar issue with my old Opel Astra, a slightly different beast from your Peugeot, but the symptoms were almost identical. "Battery sensor" is just a fancy name for a sensor that monitors the battery's health. In my case, the car struggled to start, and the lights were doing a disco impression. Have you tried checking the battery charge with a multimeter? A healthy battery should read around 12.6 volts when the engine is off.

Yeah, I've checked the voltage, and it seems okay when the engine's off. But what exactly did you end up doing with your Astra? Did replacing the sensor fix it, or was there more to it? I'm trying to avoid throwing parts at it without being sure. What's a multimeter anyway?

A multimeter is an electronic measuring instrument that is often used to measure voltage, current, and resistance. With my Astra, replacing the sensor did the trick, but only after a proper diagnostic check at the garage. See, these sensors can cause havoc if they're faulty, messing with the charging system and leading to all sorts of electrical gremlins. Best bet is to get it checked by a pro – could save you a lot of hassle in the long run.

Cheers for the advice! Took it to a local mechanic, and you were spot on – faulty battery sensor. 315€ later, and it's all sorted. New sensor, no more flickering lights, and the engine starts like a champ! Thanks again!