Mystery failure

u The owner of this 2001 Peugeot 307 1.4 wasn’t too amused when her vehicle suddenly lost power on a wet and cold morning. Her son had just serviced it for her and assured her it would be good for the winter. Stopping at a junction, the engine did not then have enough power to move off again.

Calling out her recovery service, the little Peugeot was soon delivered into my care. Running a quick diagnosis, the codes that came back were all for multiple misfire – which didn’t give too much of a clue.

The spark plugs were freshly new and I did at first suspect the coil pack, but thought I would just make a few more checks before ordering one up. This was a wise decision because, when I removed the multiplug from the coil, I found a light green corrosion on some of the terminals. There were also traces of washer fluid that had dripped from the washer jet and straight down onto the ECU.

I’ve come across this problem before with washer fluid damaging the injector plug; it’s surprising how corrosive washer fluid can be. After cleaning the terminals with an electrical switch cleaner I reassembled everything to hear the engine fire back into life at full power.

All I had to do now was protect the connection from getting dripped on again.

The washer fluid had dripped on to the connecting plug, preventing a good connection between the pins.