hello all new to forum. i have been a ford guy and swithced to chevy. just got 03 1500 with 5.3 z71. love the truck. But code p0455 major emissions leak keeps coming on. weent to dealer got new gas cap stayed off for three days then is back on. worried that this will hurt my engine just looking for some help.


thanks

 

Will not hurt engine, but you may smell fuel if the leak is by the tank. Just forward of gas tank you will find a canister. There are three hoses connected to it, one large and two small. The large one goes up and over towards the driver side frame that is connected to a evap filter valve. The filter does get dirty and clogs up and GM has a fix for it. One of the small line go to the fuel tank and the other to a evap solenoid on the engine. The solenoid may seem loose on the manifold but thats the way it is designed. You need to check all the connections for tightness and the electical connection is secure. Also check the fuel hose going from the cap to the tank for tightness. Just replace my fuel pump and the evap filter valve on the frame as I was getting a different code but all evap related.

 

thanks for the advice. i will be checking all the items you told me too and hopefully this will help.

 

My 2008 Suburban has been to he dealer 3 times for a P0455 code. I looked up a TSB on this issue, but they told me it wasn't that. They replaced the canister and the solenoid, but it didn't work.
I can't fuel the car up! It keeps clicking off the pump. Anybody have an idea how to fix it?

 

for the tank to fill...air in the tank must vent out. the vent path must be clear. the vent path is from an evap hose on the top of the tank...to the evap cannister....out the vent value...out the fresh air filter.

the other issue would be a blockage in the filler neck causing fuel to back up and shut off the pump. the filler hose and smaller vapour vent recovery hose should be clear.

 

Thanks. I will try to check these things out myself. I have already spent 900 at the dealer with no results.

 

I'm still having problems with the evap system. I can't pass inspection

 

is the filling problem resolved?
is the problem the evap monitor won't run? It is most likely temp dependent; meaning the monitor will not run and complete if the ambient temp is to cold. In many states a non running evap monitor is allowed to pass for this reason.

 

I don't believe it is a temp problem. This issue started a year and a half ago when the dealer replaced the fuel tank sending unit/fuel pump on top of the tank. Ever since then, I have been unable to fuel the truck. I've seen videos on youtube showing what the problem could be, but the dealer can't think outside the box. The dealer tells me to buy a new truck! Not from them.

 

that is not what i'm saying

the filling problem is separate from the evap monitor running