So the used 2.7T A6 with 103,000 mi was on its second full tank ( first tank had a btl of Lucas Oil upper engine lube and cleaner) added no problem. Several days go by another fill up premium Mobil gas , I added half a bottle of Lucas Octane booster presumably to help the fuel sys in this nasty Winter we are having here outside of Detroit.All is well bopping around doing errands ( 10 miles on newly filled tank) As I turn down my street the check engine light comes on. Did I cause this ?? Something tells me 02 sensor ?? Any help or thoughts ?

 

What's the code?

 

No code yet as dealer not open til Monday. Light came on shortly after adding the octane booster. Also when it's cold and just started up a noise that sounds like dripping or splashing water can be heard and a very light drip of a clear non greasy fluid drips from where the U brackets are on the exhaust just past the cat converters I believe?? Once hot no sign of this.

Does octane booster have lead which may set off a sensor either 02 or cat based ??

 

Also no belly pan when purchased , seller is meeting me Wednesday with it . Didn't know if that matters bnut also curious as to how important it is . 0-40 Mobil 1 going in her right now!! I think I should have skipped anything other than good gas going in the tank. I hope I didn't just cause myself a large expenditure.... Thanks in advance to any and all for any help and comments, advice etc..

 

Somewhat pointless to comment without a code... For your reference, I would purchase a VAGcom or at least a cheap OBD II reader for your future use. It will be cheaper than going to the dealer everytime you have a check engine light. BTW, CEL for Audi tends to happen a lot. Welcome to the club.

 

Oil change completed , while dripping I was checking out the vac hodes and such and found the hose that connects to the passenger side valve cover completely unattached. Reconnected it and the CEL is still on. Going for a drive maybe it will go off ??

 

Probably it will still come on unless you erase the code(s). Take it for a spin to AutoZone (if you have one in town) and have them scan and erase the code.

As far as the booster, I highly doubt it caused your CEL to come on.
Most likely it is just a coincidence the CEL came on right after you added it.

 

the CEL could be related to that hose being unattached but going for a drive isnt going to make it go out. You will have to drive it up to a week before it will correct itself. Go to a local parts store and have them pull the code and post it back here.....otherwise everyone here is guessing.

I agree with Chefro though, chances are, it is just a coincidence that your CEL came on after the additives were used.

 

Thanks everyone for the help and the info I will report back when I get the code !!!

 

What burb of detroit are you in? I am south in Monroe county if your close I have Vagcom and could read/clear codes for you.