I have a 2008 C300 4matic that, after installing KN air filters, and using the step down linkage on the parkway to accelerate to 65, a Service Engine Soon code was displayed. Before I spend large buckagge at a dealer, I read here that KN might foul the Mass Air flowsensor, and after some Googling, found out how toclean it. I have done that, but presume the trouble code willstill reset until I clear it. Does anyone know how I can clear itmyself by pushing some buttons or whatever? If you can help- or advise me on what I sould do,please email me directly at wszypszak@comcast.net. The car is running fine, so the trouble code surprised me because I have had the KN'sin for about 2 months, and it was only when revving the engine that the code came on, leading me to suspect the condition I mention above. In advance,thank you forreading this and any advice you might offer.

 

CHEK TO ENSURE THAT YOU REINSTALLED THE VACUUM LINE PROPERLY!!!!! I have done this on more than one occasion and seen it on the boards as well!!!

 

Sorry to say, the KN's are the issue. They suck.

 

I cleaned the Mass air flow sensor, reinstalled the OEM filters, disconnected the battery for an hour, took a test drive and VOILA! no more SES signal. So, it was the KN filters. If anyone wants to buy the KN filters- only <200 miles, make me a reasonableoffer and they are yours. They did not work in mine, maybe they will work in yours. Seems like it is an individual car problem.