I don't get it. I just recently installed a K&N aircharger on my 05 S2K. I had the negative disconnected from the battery while I was doing this. Once everything was up and running I put the negative back on and turned on the car. No CEL (Score!!!)....or so I thought. Next morning I wake up for work and I see the CEL. Did the search on the forum and how the "How to check Vac line" thread. Everything was done right. I made sure the hoses were tight and secure. Reset the battery and pulled the fuse from under the steering wheel. No CEL. Drove to work and everything was fine and dandy. Got off of work and CEL was back on. So today I switched the valves for the hell of it. Did everything and no CEL. Drove around and stopped somewhere to get food. Got back into the car and still no CEL. Just went out to Dave & Busters with no CEL. Got out and there's that CEL again. I have no friggin clue what's going on.

 

I don't feel like searching. What code is P4011?

If you really are stuck, I'd suggest reinstalling your stock airbox and reset the code to find out if it reoccurs. If it does not and you installed the K&N again AND the CEL comes back then I'm lost.

 

Sorry I meant P0411.

 

I kinda thought you might've meant that. Guess I'm lazy cause it's late. Well, if you put your stock airbox on and receive the same code after a reset, then it could be a couple things. Either you have a leak, or maybe a faulty air pump. I would recheck all tubing for cracks or leaks. Make sure none of the tubing contacts any belts or pulleys, and that they are well secured.

I know the double checking, triple checking is frustrating, but the likelihood of your air pump going at the exact same time as your K&N install seems pretty slim.

Keep checking or eventually start the install from scratch and you will find the problem. It's a fairly linear and logical flow to follow. I screwed up my AEM v2 a while back and fortunately I was lucky enough for it to be the typical backwards valve and I wasn't tracing sneaky causes like you.

 

It's pretty obvious that it's your CAI. Start from square one and try again.