P0455 Code

searay220 · September 14, 2009

I have a 06 Sierra 2500HD crew,4x4,6.0L. I have been recently getting a check engine light along with a "tighten gas cap" on the display. Well tightening the gas cap doesn't help.I bought a scanner and am getting a P0455 CODE. It has something to do with evaporative emission large leak detected the scanner says. OK now what? Has anybody been through this?

txab · September 14, 2009

First, have your gas cap checked. They can go bad even on an '06.

Search is your friend.

http://www.gm-trucks.com/forums/index.php?...st&p=553188

P0455 Search on GM-trucks.com

searay220 · September 15, 2009

Do you think it could be that easy????

txab · September 15, 2009

Do you think it could be that easy????

The gas cap? For some it has been that easy. It's a place to start.

233monte · September 16, 2009

The odds of you fixing an evap leak at home are not good. 455 is a large evap leak, so slide under and see if any vapor hoses are off. If not take to a garage.

searay220 · September 16, 2009

So follow and inspect the hoses that run out from the gas tank?

Rudy35 · September 16, 2009

So follow and inspect the hoses that run out from the gas tank?

I had the same code and code 449 and my vent vent valve selonoid was bad. Dealer wanted $111.00 garage price for the updated version. I bought the original at RockAuto for $17.00. It fixed the problem. I'm ordering another one because $17.00 every 5 years is better than $111.00 or more!

233monte · September 17, 2009

Yes, follow the hoses from out of the tank. Check them around the carbon canister, vent valve etc.

searay220 · September 17, 2009

Well today I replaced the gas cap and cleared the codes. So now I'll just wait and see what happens. In the mean time I will inspect the hoses for any damage. I did want to mention that the code I cleared today has been the same the only difference it said "small leak" instead of "large".

Not sure if that makes any difference?

searay220 · September 21, 2009

Well the gas cap replacement was not the fix. This morning the trouble occured again. I really would hate to bring it somewhere and pay someone to fix it. If it's something I can do I will always at least try. So now I'm thinking vent valve selonoid. Visually I don't see anything but not really sure what I'm looking for.

searay220 · December 4, 2009

OK I finally got to the truck this week. Original problem was the check engine light on and generating a P0455 code. I purchased the new vent valve selonoid for an auto parts store that sells ac delco parts. I can get you the new part number if you like. I found the info on this website but not sure where. The new part comes with a new design seloniod and a remote vent/breather. $101 at the store but also needed 15 ft of 5/8 heater hose and 4 clamps. The new design you run the heater hose up over the tranny and attach the breather. I'll find the instruction if you pm me. So I put me original gas cap back on which is good because it has the leash to keep from loosing it. The hose and clamps ran about $20 and I had the wire ties. So for less than $125 and about 30 minutes the job is complete. I cleared the code and so far so good. Very very easy to do.