I recently installed a K&N drop in air filter. My car has been throwing a code that triggers the check engine light. I have reset it twice. From what I can tell from an OBD2 machine it is either an O2 sensor or the mass air flow sensor. I spoke to the service manager today at the Audi dealer and first thing he asked me was "did you install a K&N air filter or a oiled filter in the car?" My answer was yes of course. He said a very common failure for the mass air flow sensor was using oiled air filters. He said it happen frequently... Is this true? What do I need to do besides the sensor? He said if Audi sees you are using a K&N and your car is under warranty, if the mass air flow sensor blows they will not cover it. SHould I go back to the old filter?

Thx!

 

i got a short ram intake on my a4 and it didnt throw a code. try using that carb cleaner spray stuff to clean the MAF sensor... it should be able to take most of that oil off of it!

 

It is BS, its their way of blaming it on the filter. I have ran K&N filters on my A4 since I bought it new in 2000 and on my Eclipse that I had for 11 years. Never had an issue with them.


Maf sensors can blow out if they are pushed to their max all the time.

 

the oil from the filter if it is too "heavily" applied has a tendency to get collected onto the small wires of the maf. Get some CRC Mass Airflow Sensor Cleaner at local auto parts store and follow instructions on can. Takes about 5-10 minutes to do if you have the 5pt security torx bit. About 45 minutes if instead of the proper 5pt bit you have a dremel and a flat-headed screwdriver(ask me how I know). Either way its an easy fix. Probably a good idea to go ahead and clean the maf everytime you clean and re-oil the filter. Good luck man.

 

Its brand new. No extra oil.

 

Brand new are over-oiled from the factory. I shake mine off(not gently)after I clean and oil it, as well as clean the maf everytime. The reason it's a problem on these cars is because the turbo draws significantly more air at a higher velocity then a naturally aspirated(n/a) engine. The filter manufacturers basically soak the filters in the oil before packaging and for most engines (see n/a) thats not a problem because the velocity of the air will usually not carry the oil to the maf. Don't take my word for it though...

 

^^^ yeah plus what do u have to lose?? 5-10$ on the CRC Mass Airflow Sensor Cleaner. compared to [ur other options/guess] a new MAF or O2 sensor...

 

I have heard the same thing on the A6 forum. Either shake the K&N or let it drain real well before re-installing. I've had one for 50k miles with no problems.