The check engine light came on in my 2009 Dodge 3500 with a 6.7 Cummins Diesel. The code that is being thrown is P2002 which has something to do with the AFTERTREATNMENT DIESEL PARTICULATE FILTER. The dealer is saying the part is $1500 +! According to what I've read that filter was supposed to clean itself out. I also read it could be the air filter, I replaced it but that didn't help. Is there a way that I can clean it out so I don't have to replace it?