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

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

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.

Your Answer

Add photo

Related Questions


Looking for a Used A4 in your area?

CarGurus has 12,956 nationwide A4 listings starting at $1,800.


Search Audi A4 Questions

Audi A4 Experts

#1 Deathjam4
Reputation 2,580
#2 FordNut
Reputation 750
#3 lukeyramone
Reputation 450
View All

Related Models For Sale

Used BMW 3 Series"
1,577 Great Deals out of 39,374 listings starting at $1,500
Used Audi A6"
139 Great Deals out of 6,443 listings starting at $1,995
Used Mercedes-Benz C-Class"
808 Great Deals out of 31,754 listings starting at $1,900
Used Audi S4"
51 Great Deals out of 897 listings starting at $3,500
Used Audi A3"
68 Great Deals out of 4,070 listings starting at $2,500
Used BMW 5 Series"
672 Great Deals out of 18,836 listings starting at $1,500
Used Honda Accord"
1,263 Great Deals out of 78,305 listings starting at $1,395
Used Ford Mustang"
726 Great Deals out of 41,151 listings starting at $900
Used Audi A8"
41 Great Deals out of 1,807 listings starting at $3,995
Used Mercedes-Benz E-Class"
746 Great Deals out of 22,571 listings starting at $1,850
Used Chevrolet Camaro"
813 Great Deals out of 39,018 listings starting at $2,650

Used Cars For Sale

2017 Audi A4 For Sale
7 Great Deals out of 6,155 listings starting at $35,000
2016 Audi A4 For Sale
10 Great Deals out of 321 listings starting at $24,999
2015 Audi A4 For Sale
10 Great Deals out of 357 listings starting at $21,890
2014 Audi A4 For Sale
42 Great Deals out of 800 listings starting at $16,695
2013 Audi A4 For Sale
65 Great Deals out of 966 listings starting at $12,950