Peugeot 107 Undervoltage Error

Sounds familiar! I had similar gremlins with my old Renault Megane. Dash lights flickering like a Christmas tree, ABS throwing a tantrum, the whole shebang! Turned out to be a dodgy voltage regulator. Have you checked the voltage across the battery terminals while the engine's running? Should be around 14V. Also, any signs of corrosion on the battery terminals themselves? Even a little bit can cause a voltage drop and mess things up.

Cheers for the reply. I'll check the voltage across the terminals when running. Where exactly is the voltage regulator usually located? Is it easy to get to?

On the Megane, it was built into the alternator, a right pain to get to! Usually they are near the alternator, but I'm not 100% where it is on a 107. Honestly, if you're not confident tracing wires and testing stuff, it might be worth popping down to a workshop. Electrical gremlins can be a real headache and it's easy to fry something if you're not careful. They can do a proper load test on the battery and check the whole charging system.

Thanks for the advice. Took it to a garage, and you were spot on. Battery was heavily discharged and defective. New battery fitted and all sorted for 290€.