Xpri

I've had the CEL come on twice in the last month and then go out a couple of days later. Dealer could not find any issues last time except a few engine misfire codes. Anyone know what causes the CEL to turn off ? Is it a time interval or the number of engine starts ?

Sprinty--Whitewagon

Then the CEL can go off on its own and not return. An example of this would be the loose gas cap CEL.

Tanner

Though some of the faults should be stored in the history

irenesbob

FWIW: I had similar problem for about a month - the CEL woiuld come on, then just go out after a few days or after numerous engine off/on's the same day. The dealer diagnosed as something like "defective low pressure fuel sensor" (is there such a thing?). They replaced it about three weeks ago and the CEL has not come back on.

KeeperPA

This has happened for the first time with my 07 B7 3.2.. Dealer could not find any codes stored. The CEL came on and went out a few days later again. Bringing the car in again tomorrow.

Any ideas?

Xpri

Eventually they said there was a lot of carbon build up and wanted to do some type of fuel/intake treatment at $200. This does seem to have solved the issue but I still have some cold start issues that need addressing. I think the cause is either low pressure fuel pump or injector clogging. Let us know what they tell you.

KeeperPA

Brought the car in this morning. CEL still on. Some rough idling initially upon start up, then normal idle. Awaiting a call from them hopefully with a cause and solution. At least I got an A6 instead of a beat up A3 for a loaner this time.

Xpri

remove the intake manifold next week and take a look.

KeeperPA

I'm assuming that would be covered under my warranty? No call yet from the dealer.

Tanner

... if you're getting CELs and they can't resolve it they do the last thing which is taking things apart and cleaning it. If you're under warranty it should be covered.

I'd be interested in seeing if it's carbon buildup or oil deposits on the intake valve.