Code P0455, large gas leak

ALEXTTT

MEMBER
2005 PONTIAC G6
3.5L
6 CYL
2WD
AUTOMATIC
105,000 MILES

My car is throwing a P0455 code for large gas leak. Canister purge valve has been replaced and gas cap. There’s no visible sign of leaks or smell. Will a vapor canister or carbon canister cause a gas leak?

Saturday, October 24th, 2020 AT 7:41 PM

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Hi,

The code indicates a large leak, as you know. That doesn't mean it is leaking gas, but rather fumes from the fuel in the tank. If it is a large leak, usually it is something you can find. What I suggest is to check things like the filler tube where you place gas in the tank. I've seen them rust and a hole in them causes the issue. Also, something could be disconnected.

I attached a pic below that shows the EVAP system's routing. I need you to first check to see if you can find anything disconnected or damaged (cracked, dry rot and so on)

If you find nothing, the next step is to smoke test the system. This will require a special tool that introduces smoke into the EVAP system via a low pressure port. Once the system has smoke in it, it will leak the smoke where the problem is located.

Let me know if this helps in any way or if you have other questions. If you do find the issue, let me know.

Take care,
Joe

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