Peugeot 407 Engine Problems

Take it to a Peugeot dealer or mechanic and have a diagnostic check done to isolate the cause.

Peugeots of this era were not known for the high standard of their electrical systems. Even when new, they gave trouble, in fact. But to find your problem, here’s my first question: Have you altered or added anything to the car that runs on electricity? This could be a new stereo head unit, amplifier, extra gauges to monitor the engine, auxiliary lights or even a sat-nav or dash-cam system. Any of these additions could be somehow remaining powered-up when you lock and leave the car each day, flattening the battery overnight.

Does the car have an alarm system? These are notorious for draining batteries and older ones especially so. Have you checked things like the light in the boot? If this stays on due to a faulty micro-switch, you could easily have a flat battery next morning. Find a dark place to park the car and then have a good look around it for any signs of a light stuck on somewhere.

In some cases, you might find the cause of the problem is the body computer which is randomly switching on various systems (including even the headlights) when you’re not looking. By the time you go to the car next morning, the lights are off because the battery is completely flat.

RENAULT doesn't market a diesel engine here, so rule that out. You could consider a VW Golf diesel. Both the Peugeot and VW diesels are well built, reliable and economical so that would probably be the best overall option.