Check the rubber o ring on ur gas cap. If its shot get a new gas cap. Otherwise just tighten ur gas cap and clear the code.

 

Well is the gas cap loose or the o ring cracked on the cap?

 

Yup, as they said, first thing check the cap, make sure it is tightened till it clicks, check the o-ring that it is not dry and cracked. Clear the code see if it comes back, next step replace the cap, if that's not it you may have a leak somewhere else. I'm tracking down the same code on the wife's Infiniti right now, replaced the cap and it's still setting the code.

 

replaced my locking gas cap with O.E. one and no codes yet. thanks guys hopefully that takes care of it.

 

I would replace that locking cap with a non locking one before winter comes or you will be stuck with a frozen lock on that cap. Thats why i dont use locking ones anymore!

 

Aftermarket gas caps don't seal like OEM gas caps, I know this is a fact for Chrysler products.

 

Had to get a new evap and relocation kit for mine. Dealer told me it was the gas cap, changed it, light and code came back after a couple months. Did some searching on the net and found alot of people with the same problem.

 

gas cap didn't solve it. the codes came back and still tells me the cap is loose

 

Does it tell you its loose, or your just getting EVAP code? because in order to really find it, most dealers do a sort of smoke test in the fuel system. They will charge between $90-$100 just for the test, but most will deduct that if you have them fix it, when it is found. Its not harmful per 'se to drive it if thats the only code there is. It will not harm to vehicle at all...just annoying light.
But the smoke test will show where the leak is in the system.

 

evap code could also be a bad purge solenoid. i would just delete the code in the PCM so the computer cannot throw the code. evap is just emmissions BS anyways.

 

EVAP VENT VALVE, Cheap at rock auto, will probably be your problem. I've had to change them on two out of my last three NBS's

 

EVAP VENT VALVE, Cheap at rock auto, will probably be your problem. I've had to change them on two out of my last three NBS's

Only code I ever got on my truck was this. No info or reason at all why, but '06 trucks seem to pop up with this all the time.

 

http://www.1aauto.com/1A/Drivetrain...b_api_nobr&utm_medium=comparisonshopping&utm_source=google_base&utm_content=ACD

apparently 1AAUTO cheaper.

 

it has been telling me both the gas cap is loose and throwing the check engine light on for evap codes. just picked up a vent solenoid for $31 and see if that cures it.

 

solenoid or valve? there is a difference. I made this mistake when my first one had this issue, everyone told me the vent solenoid, ended up getting the purge solenoid that goes on the fuel rail on the engine, didn't fix it. The vent valve is what you are likely needing.

 

What's the situation on this issue? Definitely vent valve solenoid? My 06 is doing the same thing, cap has been replaced and according to the shop, so has the needle valve where they hook up the smoke machine because that wouldn't seat properly after they removed the machine. That was 4 months ago, now about once a week the check engine light comes on at the second I start the truck. Turn it off with the code reader, could be a day, could be a week, but it'll come back on. Someone got some info on what evap parts exactly are running/turning on or off/pressurizing on start up that could cause this code? And where is this test port they're talking about having replaced?

 

My 07 NNBS crew cab was doing the same thing. Replaced the purge solenoid under the driver's side back door then had a buddy at the GM dealer clear the code for me. Never came back on. 99% of the time the gas cap is NOT the issue!!

 

Vent valve by the fuel tank is what fixed mine. DIC was telling me to check gas cap, then the Check engine light came on a while later. No problems since

 

I would replace that locking cap with a non locking one before winter comes or you will be stuck with a frozen lock on that cap. Thats why i dont use locking ones anymore!

They are easily bypassed by grabbing the cap with both hands and pushing down until the two halves seperate.

 

I have a 2005 5.3 1500 and have been throwing the P0455 (Large Leak Detected) for a few months now. I was also receiving the "Tighten Gas Cap" message on the DIC. I picked up a new gas cap from GM and both issues still remain. The "Tighten Gas Cap" message comes up daily after I drive for 5 minutes or so.

I am thinking that it is time for the next phase and replace the Vent Valve Solenoid. Where is the best place to pick this up? GM wants to sell me the replacement part with the relocation piece for $175!!!

Also, I have the ScanGauge II hooked up to my truck to monitor trans temp, it allows me to monitor the Fuel System Loop Status and this status goes from open to close on a daily basis. Would this be referencing the Vent Valve? If it is would that mean that my Vent Valve is working correctly?

EDIT: I do smell gas vapors after I park my truck and since this code and there is a pulsing noise coming from that area that is really subtle.

 

I have an 04 sierra throwing up the same codes... can you still pass smog like that?
Also who knows how to fix it?

 

Think I found my issue tonight. I pulled the valve off to go get a new one and noticed it had been replaced/repaired before, someone had cut the hard plastic line going to it and put a 6-8" rubber hose section on and clamped it. I pulled it off and noticed dirt tracking inside the rubber hose where the one end was clamped to the hard line, like the clamp wasn't tight enough and it was periodically leaking, causing the small evap leak code. So I cleaned it up, replaced the clamps, and hope now the code doesn't come back.