P0442 Help

spock · September 7, 2009

Anyone had the P0442 DTC before? What was the fix? I keep getting it every couple months and it's getting old seeing the CEL on. Light usually stays on for a couple weeks then goes off by itself. I changed the Fuel cap three weeks ago and it hasn't gone away. I have never gotten the "tighten fuel cap" DIC message. I know it's a leak in the EVAP system but just wondering if there is a typical cause that someone can point me to or if it's gonna be a PITA to track down. Any help is greatly appreciated.

kwistofoo · September 7, 2009

i had an issue like that.. also had trouble filling up without the pump kicking out repeatedly. turned out to be the evap canister purge valve.. easy and cheap fix.

i don't remember if that is the same code, but i had the CEL on and DIC indicating to tighten the cap.. similar code for sure, just not certain of the actual number i had

Poncherello · September 8, 2009

I kept getting DTC P0455 on my 05 Tahoe. I just replaced the Fuel Tank Evap Control Valve today, GM part # 25932571. I was also getting the Tighten Fuel Cap warning. Replacing the fuel cap didn't help. The part was $22+ tax at the dealer and took about 20 minutes to replace. After about 30 miles no CEL yet....I'm hoping this cured the problem. The old part had some stuff rattling around in it when I shook it so I'm guessing it was definatley bad.

spikesputnik · September 17, 2009

Spock- I've got the same thing going on, except my "tighten cap" light came on a couple of times. I checked the cap, which was already tight. Then the CEL came on and got a 0442 at the auto parts store. The CEL has been on for a week or so now with daily driving and on a second tank of gas.

Could my sysytem still be "pissed" about the supposedly loose cap?

I heard on one thread that the battery can be disconnected/reconnected and it will reset/erase the CEL, which will come back if there is a persistant problem. Can someone confirm this to be true or false?

SierraJoe1110 · September 17, 2009

I have a 1999 do i dont have the DIC like you guys, but i see the guy who started this thread is from the great state of mass like me where the roads are awful... My check engine light keeps comeing on when i go over extremly bumpy roads(which is pretty much all of them lol) and i think that is the code that comes up when i have the mechanic at work clear it... and i also have a new gas cap. something is just getting shaken loose and i cant find it. Any ideas if i have the same problem?