you're right. the new purge solenoid did not clear the code. I'm installing a new

 

I have the same code (p0455) on my 04 5.3L silverado. Did the new canister fix your issue?

 

he didn't replace the cannister. try a vent solenoid if you want to guess.

 

Sorry for the late reply as I was out of town. Yes, it was a new vent solenoid that finally cleared the code.

RickR90s

 

@RickR90s Thanx for the reply. Did you do the work yourself or have a mechanic do it? If so, What was the mechanic cost? or What was the estimated time it took you?

 

Hello, I did the work myself. It's as simple as crawling under the fuel tank to disconnect the old part and plug in the new one. It took me about 15 min. total, including the time to plug in my OBDII scanner to clear the code.

Good luck,

RickR90s

 

I have same code and when I shut off my truck it sounds like pressure releasing

 

I have an 07 Silverado 2500 HD 6.0 that continually says tighten fuel cap, but it only happens in the morning. I drive the truck through out the day start and stop and I don't get that message again. Changed the cap to no avail, I'm thinking the vent solenoid might be my issue. On that topic but veering towards another, what is the possibly this would cause the truck to shut off hard and also a shifting issue? I have reset the memory of the transmission with my Scanner and it will shift fine for a while and then start hitting second and third hard again, 2nd harder than 3rd unless I lift off the accelerator as if I we're driving a manual. Trans serviced religiously every 30k miles and never towed much weight or plowed much at all. Also seems to lack power under a heavier acceleration, but not consistently. I'd say it feels as if the drive train is tight like calipers hanging up but that's not the actual case. On this topic I've swapped the throttle body with my other 2500 thinking it was a TPS issue but no change(cleaned TB during this swap) and lastly checked the intake for leaks via carb and choke spray as well as propane. Any advice/input would be helpful.

 

I have this same issue. Replaced the gas cap but the message returned. Will not fixing this cause damage or risk of explosion or some other problem? Or can I safely ignore it? (I'm basically "driving this thing into the ground" and can't afford constant repairs as I save up for a new model, but if there's a safety risk, I'll fix it).

 

the only danger is to the environment...smog formation.