TominClarence
New member
Hello .... I am hoping I'm at the right forum. I have a 2007 GMC W4500 the is giving me a code, P0299. (Turbo underboost condition) My turbo boost sensor reads 14.4 lbs key on engine off. I thought it should have read "0" so I replaced it. Same thing, 14.4 lbs. with the new sensor. Did a little research and apparently it is supposed to read that? next check was the waste gate. It was closed, not stuck open. I put a manual gauge on it and just sitting in park and revving it it will go to 4 lbs of boost. Test driving it, under a load it still only reaches 4 lbs of boost. I removed the EGR valve and checked to make sure it wasn't open and therefore bypassing pressure back to the exhaust. It was closed. I am thinking no that either A) I have a weak turbo or B) a possible leak in the inter cooler. Does anyone else have any insight? These turbo's are expensive, I hate to throw one at it ... Uggggggggh ... Thanks for the help !
Truck has 130,000
Truck has 130,000