Just bought my A4 with the check engine light on the previous owner brought it to his friends shop I guess and he said he thinks it is an O2 sensor. I took it to Autozone on the drive home just to check it out. Im planning on getting the OBD cable but just wanted to know if anyone can tell me now so I dont run into any problems

CEL Code: P0422

Definition
Catalyst efficiency low-bank
Explaination
The oxygen sensor monitor the Catalytic Converters ability to store oxygen.
Probable cause
1.) Catalytic Converter defective (failure possibly due to # 2,3, or 4)

2.) Engine misfire or running condition

3.) large vacuum

4.) Engine oil leakage into exhaust-valve guide seals, piston rings


Any one know what this code means the guy that helped me couldnt tell me anything?

 

You only have 2 02 sensors, one before and after the cat. This code is for the one after. Its not going to make the car run any different, just throw a cel. You can reset the comp and see if it comes back. If it comse back and the cel bothers you enough, then replace the 02 sensor after the cat. I usually just get the universal kit for around $70. Same sensor as ecs tunning sell for $150 or what ever, just have to connect 4 easy wires.

 

I thought the O2 sensor behind the cat doesnt do much and would be a waste of money to replace I really could care less about emissions.

 

it monitors the condition of the catalyst, if you dont care about emissions then ignore the code. you will just have a permanent CEL. but that code could mean either the O2 sensor is bad, or the cat is melted and restricting your exhaust flow. but who cares about that code right?

 

If you replace that o2 sensor, reset the ecu and the cel comes back on, you might need a new cat. Meeeoooww.

 

I had the CEL turned off because I needed to go for a state inspection the next day as i was pulling in to the garage parking lot my CEL popped on again. So im guessing I should just go ahead and replace the O2 sensor wheres the cheapest place I can get one just in case it is my cat that needs replaced

 

Well I just replaced the rear O2 sensor I got an OEM one from ECS pretty easy to install anyway after I disconnected the battery for about 15 mins I turned the car back on and I still had the CEL. I scanned for codes again and it was still showing the same P0422 I cleared the code and if it pops back on again im thinking the next step would be a new cat?

P.S. Still havent gotten it inspected yet and already got a letter from the DMV with a suspension date for the registration. F*** emissions testing im moving to Kansas lol

 

Yeah, if it comes back then you need a new cat. Here's an idea though, about how long did it take for the cel to come back on? If you don't have the money to buy the cat yet, maybe you can slide by the smog test by bringing the scanner with you and clearing the code right before you bring the car into the test area. just make sure to do it like a block away and hide it in the glove box or something lol.

 

I have the money for the cat but wont I get a fail for the readiness status if I clear it just before the inspection?

 

LOL, moving to Kansas. I have a similar problem, guess what I did to my cat yesterday? (and guess who moved to Kansas a couple months ago...)