Hello, Having a P0455 trouble code on my 05 Silverado 5.3L non-flex. There's a ton of these posts on here but i can't pinpoint the problem. I replaced the gas cap with a genuine gm cap. cleared the code and it comes back. I replaced the purge valve, cleared the code and it comes back. I don't have a problem with slow fueling, fills up at a normal rate. I will say I'm guilty of trying to get every last drop in there when i fill up, I now know that I should't do that. The evap canister solenoid is behind the tank just north of the rear axle. Could this still be the problem without the slow fueling symptom? Other than the trouble code being triggered every 3 or 4 days the truck has no issues. I know I will not be able to remove the hard plastic heat shrinked tube off the canister, I can't seem to figure out the trick in disconnecting the clip connector. not hard getting my hands on it just not sure how the press or pry or what. Any help will be greatly appreciated.
uposb4
this code says the fuel tank has a big leak. many items can cause this . I would remove the charcoal canister and check for cracks since you over fill the fuel tank. then the vent valve on the under bed could be stuck open. remove the big vent tubing check for any charcoal in them .. so if this is with debris in the venting tubing you will need to replace the canister.. then if it continues the vent valve replace that ..
you replaced the purge / vacuum valve on the intake manifold well that is the testing of the fuel tank leaks.. PCM measures the vacuum changes when the evap system test is performed.
the vent valve if plugged stuck closed will cause the gas fill nozzle to click off..
check the fuel tank pipe as that can have a rust hole in the welded area of the pipe support.close to the cap area.
if that is it then use some metal paste patch on the hole then put some rust proofing material/paint over the patch.
you replaced the purge / vacuum valve on the intake manifold well that is the testing of the fuel tank leaks.. PCM measures the vacuum changes when the evap system test is performed.
the vent valve if plugged stuck closed will cause the gas fill nozzle to click off..
check the fuel tank pipe as that can have a rust hole in the welded area of the pipe support.close to the cap area.
if that is it then use some metal paste patch on the hole then put some rust proofing material/paint over the patch.
How is the gas cap flange on the filler neck for overall condition???
Is this vehicle run off road at all???
Has somebody worked in the engine bay recently???
Has somebody loosened up the little green cap (on the tube) near EVAP system in the engine bay???
j cat is on point in what to do.
Is this vehicle run off road at all???
Has somebody worked in the engine bay recently???
Has somebody loosened up the little green cap (on the tube) near EVAP system in the engine bay???
j cat is on point in what to do.
As best as I can tell the neck and the lines appear in good shape but just looking and feeling is not saying much. I hit a dirt road 2 to 3 times a year tops. No work done other than replacing the battery and the green cap has not been mucked with. I'm going to replace the evap canister solenoid as soon as I can figure out how to get that clip connector loose.
Instead of replacing every EVAP part on a guess, find a scan tool and do a I/M Readiness Test with the EVAP system electrical. If it passes, the electrical portion is good, ...onto the physical portion.
Remember, … you have 14 year old vehicle and any EVAP component could be failing, ...not just sensors or switches, could also be seals, gas tank nozzle etc.
Next step is to "lightly pressurize" the EVAP system (with a second person pumping away on a bicycle pump) to no more than 1 to 3 pounds of pressure. Any more pressure than that, EVAP system damage will occur. Best time to do this test is when the gas tank is filled to brim of the gas filler nozzle. You want to reduce the air volume of compressible air in the fuel system for a quicker response to pressure with available air in the fuel tank.
Use can use your old gas tank cap as a modified pressure adapter by using a RTV "adhesive" sealant to pressure sealed 1/8 inch NPT - 1/4" brass barb, then stepping up to the hose size that will surround the tire pump discharge valve to a point there is absolutely no pressure leakage when pumping. As a general rule, the EVAP system will only hold about 20 inches of water pressure or 0.722 psi before the gas cap releases.
You gotta keep a positive pressure on the fuel system to find this leak.
Use a healthy solution of dish soap and water in a spray bottle and apply on EVAP lines, connections, sensors, fittings mounting points and look for any amount of bubbles building up in that spray area. It's the same method used to look for gas line leaks in a home. Spray on every connection, mounts, sensor, switch, cap, fitting within the EVAP system, Where the bubbles build up, ...that is the location of the leak.
Remember, … you have 14 year old vehicle and any EVAP component could be failing, ...not just sensors or switches, could also be seals, gas tank nozzle etc.
Next step is to "lightly pressurize" the EVAP system (with a second person pumping away on a bicycle pump) to no more than 1 to 3 pounds of pressure. Any more pressure than that, EVAP system damage will occur. Best time to do this test is when the gas tank is filled to brim of the gas filler nozzle. You want to reduce the air volume of compressible air in the fuel system for a quicker response to pressure with available air in the fuel tank.
Use can use your old gas tank cap as a modified pressure adapter by using a RTV "adhesive" sealant to pressure sealed 1/8 inch NPT - 1/4" brass barb, then stepping up to the hose size that will surround the tire pump discharge valve to a point there is absolutely no pressure leakage when pumping. As a general rule, the EVAP system will only hold about 20 inches of water pressure or 0.722 psi before the gas cap releases.
You gotta keep a positive pressure on the fuel system to find this leak.
Use a healthy solution of dish soap and water in a spray bottle and apply on EVAP lines, connections, sensors, fittings mounting points and look for any amount of bubbles building up in that spray area. It's the same method used to look for gas line leaks in a home. Spray on every connection, mounts, sensor, switch, cap, fitting within the EVAP system, Where the bubbles build up, ...that is the location of the leak.
the vent valve does get stuck open for many. so remove the valve and check it out if it is open. could also wash it out and see if in the bucket you can see debris ..
Forgot about that part with all the ethanol laden gasoline out there. Follow j-cats recommendation and see what happens.
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