Mokka water sensor error

I had something similar with my Mokka, although it wasn't a diesel. Those water sensor errors can be tricky. Did you check the wiring harness leading to the sensor? Sometimes the cables get brittle and crack, causing intermittent connections. If it’s cracked it might cause a short circuit to ground, which is where electricity flows where it shouldn’t.

Good shout. I only gave the plug a quick once-over. Where exactly should I be looking for these brittle wires? Any specific spots that are prone to damage?

Honestly, it could be anywhere along the harness. But pay close attention to any points where the harness is secured to the frame or engine. Vibration can really wear them down. If you're not confident tracing electrical faults, get it to a workshop. Could save you a bigger headache down the line.

Cheers for the advice! Took it to a local place, and you were spot on – corroded wiring to the sensor. New section of harness and sensor check sorted it. Cost about 95€, not too bad.