A friend has a 2.0L FSI Audi A4, and asked me to scan it on vag com this eve as its a bugger to start and idles very low and wobbly / miss firing. cranked it up and gave it a scan and it came back with: 17479 - NOx Sensor (G295) Heater Control: Implausible Signal P1071 - 004 - No Signal/Communication I cleared the fault and it didnt come back, started the car up and it wasnt there after being run (there was no light on the dash either) the idle is down at around 720rpm according to vag com. do you think it would be worth trying a new lambda probe?
No Karl, It's bit more than a Lambda The Nox sensors is the lambda'ish sensor fitted behind the Cat, it also has control box attached to it hicking the price up to the 260 ish mark if i remember correctly I've only came across issues with these on FSI's which I think there fitted to I'd wait for it to come back
oh joy.... the problem is the idles very pap so its going to have to be done (plus he says its drinking fuel too) Ill give it a scan in a day or so and see whats up, but you reccon its that magic senor and box thats not happy. cheers Crispy Karlos
could the engine be also miss firing- the FSI range of engines are rather sensitive to poor grade fuel / carbon the seats does the engine run smooth when codes cleared? shows that the EML maps are slight off intentionally
with the code cleared it was marinally better but still miss firing at idle it seems (when reved it seems pretty smooth) - have not driven it on the road yet, the background is the lad brought the car from available car and when he got it it was a doing this same problem, very poor lumpy idle and just generally not right... they had the car back and tried to fix the fault with a "service" but since then its never been 100% right and just latley the problem has come back again just as bad so I am told (this is the first time I have seen the car as the lad is a mate of a mate) I will get the car back tomorrow eve and scan it again to see if anythings back up and have a test drive too to see how it is under load above idle the car has done 51k now so im tempted to whip the plugs out and see if one of them past its best? (I also unpluged the maf sensor just incase but agai that made no change, didnt think it would but wanted to check) if logging anything in vag com will hellp I can do that (im still learning vag com as to what to log to check for what faults etc)
before clearing faults check, then MVB 14-15 for the miss fire detection - section 4 will show up enable when checking the engine naturally sound slight off from cold, sounds like it could have a soft misfire - compression check while plugs out?
Ill see if I can get my mits on on a compression checker, and the engne was warm when I saw it... id hate to see how rough it is cold Ill have a play tomorrow if the lads free and report back. cheers very much Crispy
