Peugeot 406 Diesel Stalling Rough Running

I also drive a Peugeot 406 diesel and had similar symptoms: stalling, rough running, check engine light. In my case, it was a faulty connection to the fuel pump relay. Have you checked the cable or plug connection?

Thanks! By 'integrity', do you mean checking for voltage at the fuel pump connector when the ignition is on? Were the symptoms intermittent or progressively worse?

Yes, by integrity, I mean ensuring the connector isn't corroded or damaged, and the wiring is sound, with no short circuit. Intermittent issues can be tricky. Given the potential complexity, I'd recommend a qualified mechanic to prevent further damage.

Thanks! I took it to a shop, and it was a defective plug connection, as suspected. It cost 95€ to repair. I appreciate you pointing me in the right direction!