Earth Issue

[shao_khan]

I have a issue with the A2 - initially i had a 'random missfire' but no missfire - it was a ground issue causing the fault which I have been unable to trace, now I get occasional ABS / ESP and red Brake / oil lights / coolant lights.

I've had the car on the diagnostics at work and the only faults I am seeing relate to this initial ground issue.

ABS system is fine - been checked.
Brakes are fine, no leaks, fluid fine no change to levels.
Coolant is fine, no leaks found, levels all fine.
Oil is fine, no discolouration, no gunk - done a change and no excessive usage.

Can anyone advise where I might best look to trace this without a lot of time - common points where I might lose a connection or cables might rub through?

cheers.

 

[ksimpson]

Have you considered the brake light switch? They're a known weak point across the Audi range and can cause the warning light problem. However, haven't heard of it causing misfiring.

What engine does your A2 have?

 

[shao_khan]

Its a 1.6fsi - it doesnt actually have a misfire - it just registers one as a fault code, checked this over and it runs just fine, the fault reporting is obviously detecting a ground issue and decided this was the cause.

I suspect I have a wire damaged somewhere, which is causing the various 'reports' that are triggering the warnings, but its not that easy to find.

I'll maybe check out the switch as well just in case.