You have to watch the engine wiring on the 451, as it is kept under tension (ie, not much slack) and vibration of the engine can disconnect wiring or connectors.
I had the 451 Cdi (DPF model) and there was one wire that hung right under the engine, and could easily be ripped off if something like a tree branch went under the car and caught in the cable loop. I had to try and tie it up out the way. Never seen wiring so haphazardly laid out and fixed.