So ill tell you the whole story. My Audi is a 99.5 Quattro Wagon.

On Tuesday night i came out to my car and my front passenger tire was flat. i put the spare on and it just doesnt work very well. So i put on my summer 17" rims up front and left the 15" rims in back b/c i only have 3 17" rims (one blew up last summer on a rock) But the other day when it was 99F outside i was driving up to the store to get some lunch and the Check engine light came on. WTF ?

There is no change in RPM's, or turbo lag but its anoying having it on. Is there any way to check what the problem is or turn off the light ?

Might it be a problem that it was HOT outside ? Or could it be b/c i am running 17"s in front and 15"s in back and something got screwed up ?

Any and all answers would be vary helpful

 

Heheh welcome to Audi world Baby!

It's something you should get used to see it often.

j/k

Best thing you can do is, go to Advance or Autozone to check it.

It's hard to say what it is without knowing the code.

 

You have an Avant, not a "wagon"- represent! and get your ecu scanned for the fault code(s)regarding the CEL.

 

big wheels in front, smaller in back.....

 

Isnt it bad for the awd system to have mismatched tire/wheel size??
(No it wouldnt trigger a CEL, quattro is purely mechanical... No sensors, etc.)

 

To my understanding it is detrimental to the drive-train if there is a greater than 5% difference between the front and rear. At least that is what I have read when it comes to the Haldex cars like the TT and Golf R32.