P0171 and losing engine oil help please

[tobyg123123]

2.0tfsi cvt. I have the p0171 fault code and i have to top up the engine oil every 3 months roughly. I can't find a leak a obvious leak though. Any ideas are appreciated thank you

A6 2.0TFSI Avant

[Rob69]

How much oil in how many miles ? I think Audi spec was 0.5 litre every 1000km which still seems a lot to me, if you search around you will find that this has been a long running problem for certain petrol engines including 2 litre, don't know what year yours is but I've got a pal who had an A4 (could have been around 2008) and he got his re-ringed (presume new pistons as well) by Audi.
Your P0171 is O2 sensor measuring too much oxygen or lean mixture, could be lots of causes including PCV system leak, intake manifold leak, exhaust leak before the O2 sensor. It might also be the O2 sensor fouled with soot or oil if the engine is drinking it.

[inspectorman63]

Rob69 has the key question here. On my 2.0 tfsi it's about 300ml per 1000 miles - so if i'd only checked it once every three months it would need a litre. Shorter, colder runs seem to need more; long motorway stretches get through almost none. Be careful with thinking the "Audi spec" is 0.5 litre every 1000 km; this is more like a limit at which Audi would consider there to be a possible fault. So less than this is regarded by Audi as an acceptable rate of use.

[tobyg123123]

Okay the oil loss is probably normal then from what you guys are saying

A6 2.0TFSI Avant

[Rob69]

We don't know, as you haven't told us how much !!
Top it up to max, run it for say 2000 miles, km or whatever, then see how much it takes to refill to max. Agree with inspectorman in that the Audi spec is the limit at which they'd consider repairing it, anywhere near that consumption would be too much IMO.