Citroen C6 Fuel Filter Heater Fault

Well, hello there! I know that struggle all too well. I have a C6 diesel myself, and a few years back, I had almost the exact same symptoms. Reduced power, rough idle, the whole shebang! I spent ages trying to figure it out. Have you checked the voltage at the fuel filter heater connector? That's where my problem was. The wiring loom had rubbed through and was shorting out. I would definitely take a closer look at that connection and the surrounding wires.

Thanks for the quick reply! Interesting that you had the same issue. When you say 'rubbed through', do you mean the insulation was damaged, causing a short? Was it obvious when you looked, or did you have to do some serious investigation to find it? I'm wondering if it's worth just replacing the connector and a short section of the wiring harness as a preventative measure, or if I should try to find the exact spot that's causing the problem.

Indeed, the insulation had worn away, exposing the bare wire and causing an intermittent short. It wasn't immediately obvious; I had to wiggle the wires around a bit to get it to short out consistently and see the spark. Replacing the connector and a section of the harness is a good idea, but honestly, given the hassle, I'd suggest having a trusted workshop take a look. They'll have the right tools and experience to diagnose it quickly and efficiently. It's likely the same issue, but better safe than sorry, especially with fuel system components.

Took your advice and booked it into the local garage. Turns out you were spot on – chafed wiring to the fuel filter heater! They repaired the wiring and replaced the connector. Total bill came to 95€. Runs like a dream now. Thanks again for your help!