Mondeo Diesel Fuel Filter Heater Issue

Sounds like a plausible cause for your woes. I've seen similar issues before with fuel filter heaters, especially in older diesels. Have you checked the wiring and the plug connection to the heater itself? A dodgy connection there can definitely cause those symptoms.

Thanks for the quick reply! I had a quick look at the plug, and it seemed okay, but I'm no expert. What exactly should I be looking for regarding the wiring? Is there a way to properly test the heater element itself to see if it's actually working?

Yeah, those plugs can look fine but still be corroded inside. To properly test, you'd need a multimeter to check for continuity and voltage at the heater. But honestly, with those symptoms and the error code, plus your limited experience, I'd advise getting it to a workshop. Could save you a lot of frustration.

Thanks for the advice. I took it to a local garage, and you were spot on. It turned out to be a corroded connector on the fuel filter heater. They cleaned it up and replaced a short section of the wiring. Cost me about 95€, but the car is running much better now! Power is back, and the fuel consumption seems to have improved already.