UK-POLOS.NET - THE VW Polo Forum

Hi all
This is my first post - I’ve been scouring the internet for an answer and so far come up with nothing so I’m hoping someone here might be able to point me in the right direction…
My stepson has recently bought his first car - a 2010 1.4 petrol Polo. I’ve had the cam belt changed, changed the plugs and fitted new crank and camshaft sensors but still after around 10 minutes of driving the engine will cut out for a split second (you just see the rev counter drop to 0) then instantly fire up again and it’s fine for the rest of the journey. I’m thinking maybe it’s something to do with the thermostat opening. Any thoughts please?
Cheers
Mike

This sounds a lot like being an intermittent loss of 12V at some point in the car, maybe not easy to locate.

The easiest starting point might be running a full scale of all the controller modules to see anything/any clues appear - but not a definite route to success right away, good luck.

Ignition switch ? Known to fail on most vw’s this will probably not leave any codes in control units though

Yes it does sound like complete loss of 12V, although I’m pretty sure the speedometer doesn’t fail. I’ll have to check. The fact that it happens at the same time I thought might be a clue. Thanks for the suggestions, I’ll keep investigating…

A quick update on this problem. It looks like it was one (or more) of the coil packs that was failing under load. I replaced all four and the car has been fine since.

Cheers
Mike

Oh well - I spoke too soon.

Just as a suggestion, clean the original wiring connectors for the new crankshaft and camshaft sensors with residue 0 contact cleaner, and check that the contacts are not displaced from their housing/position in the connectors.

Ok thanks I’ll give that a go. Since replacing the coils the main code we’re getting is P0687 ECM/PCM Power Relay Control Circuit High

I’ve bought another ECM but the key needs reprogramming to use it. Waiting for an email back from the local dealer…