Quick AOS question
 

Will a bad AOS put a check engine code on the dash?

Not usually unless you persistently ignore the 007 Bond style plumes of smoke from exhaust for an extended period of time. Doing so would result in not only fouling O2 sensors, clogging your cats (:eek: - I said it!!) but more importantly mean you're at great risk of hydro-locking a cylinder or two w/ oil...

If in doubt a bad AOS or old due to time/miles it's cheap insurance to replace...

If you have a CEL just visit any large auto parts store and they'll pull the error codes gratis.

Good luck :)

I thought on Sunday on the first start of the day. About 10 degrees Celsius. I say a bit of white smoke. But it could have been dust that had collected under my car due to a bad storm the day before. I saw it again. 2 day later. But it could have been dust again. Then I got out and looked every start after and saw nothing.

I pulled the oil filler cap off to check for suction.
The light cane on the next day.

Could pulling the filler cap off made the light come on?

If it did. Will it clear it's self?

Pulling the oil fill cap off should not have tripped the CEL. Something else is wrong, and you need to scan the car to find out what. I also would not be starting or driving it until you do know.

Agreed, It came on half way to work this morning. I put her away and pulled out the old Sunfire.

Woopie

I can steel my wife's 335i.