I was dealing with a P2279 code on my 2007 Oddy for the past two months. Which means air leak, checked everything about 50 times and couldn’t find anything. Came here and read that someone said that doing a valve adjustment had fixed their code. So I went ahead and had that done. But, to my luck, that didn’t change anything. Code still came up and it was driving me nuts. Well, I had someone come check it, he put it thru a scanner, a more advanced one than mine, he said everything was fine, the only thing that seamed weird to him was that my fans were turning on a lot more than usual. My van wasn’t heating up or anything. But I figured let me check my thermostat, and it was bad. I changed it and it cleared my code. Why? I still don’t know. But that was the issue with my van and the code P2279 hope it helps someone. Before they invest in doing a valve adjustment or a bunch of other parts. Check your thermostat.