jpc

I have a 2001 A6-2.7t with around 125k miles and have had recurring check engine light problems for about 1/2 a year. It's been an intermittent problem where the light comes on and then goes off; sometimes staying on for several weeks and then finally shutting off. Sometimes stays off for weeks.

I finally broke down and bought an OBD reader to get the codes. There were three: P1113, P0421, and P0431. After resetting them, the light never comes back on immediately, and never comes on if the car is already warmed up. I have noticed a pattern where the light will be off when the car is started cold and then comes on after driving for about 5 minutes. If it makes it beyond the five minutes and is fully warmed up, then the light won't come on at all. If it does turn on, usually only P1113 code comes up. If I don't reset it for several days and then check, the same three codes are there.

Sorry for the long post, but looking for some ideas before visiting the dealer. It is scheduled for a tune-up at 125k miles (new plugs, etc.) but don't want take it in and have them tell me that I need new cats. If they needed to be replaced wouldn't the codes be there constantly without resetting themselves? Since the light does reset itself at times, doesn't that indicate a minor issue and not something major like bad converters?

Any suggestions would be appreciated.

paulroad

Instead find a good independant but Audi savy shop. Go to the area forumon Audi World that is near your home and ask for suggested shops.\


You should also return the OBD reader as you can get free readings from any AutoZone and Advance. you should buy a VAG-Com cable and software..if you plan to keep this long term and do some mods.

quickaudi:STFA

please do a search of the forum archives with the P codes - you should find something

jpc

Thanks Paulroad-
I have a very good independant mechanic, but can't always diagnose the emissions stuff.

I really have no desire to modify the car and am not much of a mechanic. Just trying to keep my car on the road and reliable. My reason for posting was to see if these codes in this pattern were anything that people have seen before. I have checked the forum for help with the codes and the suggested fixes vary wildly. My hunch is that the problem isn't severe (like bad cats) since it clears itself after a while. And, if the light is reset, it doesn't seem to reappear until the car reaches around 55-60 MPH. Then stays on for a while.

What do you think?

paulroad

www.bentlypublishers.com

you will see that they relate to the 02 sensors, usually the ones before the cats.

quicksilver 2.7

I am a new member-just joined. Love my a6 2.7t but I am having problems with the "kombie" valve. It has been replace twice in 18 months. Wher is it and can I clean it?

DasTrufel

those faults or related to the cat's, they are failing the warm up time. Looks like it's time for new cats

modset

it could have something to do with your cats in the future. right now the code is for bank 1 sensor 1. the first o2 sensor needs to be replaced(the green one), locatd on passenger side. i have the same code. about to replace mine if i can ever find a good write up.