I recently installed a K&N drop in air filter. About 150miles later the check engine light comes on. I got it checked and it is a three way catalyst error. I'm wondering if this is due to the additional air flow by the mass air flow sensor. I know there is a TSB about a false error for this. I'm getting that checked out now. But, has anybody else seen this problem? If so, how do you fix it? Does the ECU have to be reprogrammed or what?

 

What year car do you have?

 

I have a 2000 SE

 

i am assuming the catalyst error you pulled was P0420? if so, then it is covered under a 8yr/80k federal emissions warranty. per the tsb for the code, they will flash the ecu. this has cured many but some had to have the cats replaced as well which is/should be covered under the same 8yr/80k. just so nissan does not have any ammo, i would replace the filter with a paper one just so they do not cook up some idea about how the filter caused it to fail.

 

I always wondered, why does the cat need to be replaced for the P0420?

 

Too late for that. Being the idiot I am, I tossed the original air filter. I guess I'm SOL on that. Otherwise I would've just tossed it back in and seen if the error went away.

I bought this car used, so I don't know whether the original owner already had the ECU reprogrammed. You need the ECU P/N to find that out. This is supposed to show up on the CONSULT II printout. Do any of you know of another way to find that info out, without going to the dealer?

 

Ive heard about K&N filters possibly getting a slight amount of oil onto the MAF sensor, which in turn could of brought on the light, every filter comes pre-oiled from the factory, its possible for some oil to get onto the sensor, maybe you could very carefully clean the MAF sensor with elect. cleaner from Radio Shack, i doubt the higher airflow did anything. Just a hunch, i could be wrong wich i am sure i will get reply's if thats the case....

 

the original tsb stated to replace the cat but then they amended it to just flash it. it works for some and not for others. to the poster, you can pick up a paper filter at any local parts store, they cannot void anything for the filter unless they provide them free of charge. this code does not have anything do with the maf. while cleaning can help with certain issues, it is unrelated in this situation.