2009 Chevy Silverado CEL


#1

The CEL came in on my friend’s Chevy Silverado …so he took it to the dealer for diagnosis/repair. After paying $125 for the diagnosis and repair (supposedly he needed a new gas cap) he was good to go. A few days later the CEL came in. I have a code reader so he asked me to check the CEL code. It’s P0442. The same code that the dealer sited. Since we know it isn’t the gas cap what are the other most likely suspects? He says the truck runs fine. No drop off in MPG, no misfire, etc.


#2

The leak could be anywhere in the evap system. The only way to find it is to have the evap system smoke tested. Potential suspects are a leaking purge valve, a crack in one of the hoses or fittings, or a hole in an evap line from a mouse chewing on it.


#3

Yeah, I was hoping there’d be an obvious #2 reason. Maybe not, the dealer pocketed the easy $125 for a few minutes work. Read the code, new gas cap and call it good.