gave us a code of "P0455"?

2006 GMC SIERRA

60,000 MILES

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HI my partners truck came on this morning with the "check engine light" , we went to pep boys, the guy did some scan thing and gave us a code of "P0455" n told us to start by getting a new gas cap n that shuld fix it, well unfortunately they didnt hav the one we needed so we went to auto zone got it, n put it on, started truck and the check engine light still is on...? what could this be ? its a 2006 gmc sierra ..

Feb 15, 2013 at 6:56 AM

SQM

✓ASE Certified Mechanic
6,383 POSTS

Hello,

The code:
P0455: Evaporative Emission (EVAP) System Large Leak Detected.

This code gets triggered when there is a leak detected with in the fuel tank and its components for emission. It could be a gas cap, but this larger leak typically is for a stuck open vent valve for the vapor canister or could be a broken hose.
Also keep in mind that the engine light must be reset after the issue is taken care of. Otherwise, the light could stay illuminated.

https://youtu.be/ahK_eucFi-k

I have attached the diagnostics for the code P0455 below. This can determine what is the reason for the check engine light.

Please let me know of any questions.
Thank you.

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Professional Diagram for 2CarPros Members
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Sep 29, 2021 at 8:55 AM