I have a Audi 2003 A4 3.0 Manual, it has 138k it's clean and smooth.Bt today the check engine light turned on.there is nothing wrong with car performance,Any ideas whtz wrong with my car??


Asked by Feb 06, 2015 at 12:14 AM about the 2003 Audi A4 3.0 quattro Sedan AWD

Question type: Maintenance & Repair

3 Answers


Get a diagnostic code reader from amazon for like 20 bux. Hook it up under the dash where the OBD plus goes. You'll find it. Hook it up. Read instructions. Whatever code(s) it spits out, Google that sh**. A lot better than paying your stealership to do it at 70 bux plus a pop. Ta da!

Best Answer Mark helpful

So i'm keep getting these 2 codes P0421 and P0431, so do i hve to replace my front passenger side O2 sensor???????????


Sure. Not too hard. If its the exhaust o2, its a little harder. Might wanna get some penetrating oil around the threads and let it set for a while. If its not the exhaust o2, should be pretty easy.

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