Replacing the gas cap on 2006 Buick Terraza

A couple of months ago my check engine light came on and my indicator warning periodically will flash check gas cap. I read the post about the loose gas caps so I bought a new one, but the light never went off and the indicator warning still flashes sometimes. I took the van to auto zone and had them run the codes and it came back with P0449 and P0455. Can you tell me what I should do?

Asked by for the 2006 Buick Terraza
1 answer
Yes these codes are for evaporative system malfunctions. P0455 is a very large or even gross leak and a P0449 is for a defective Evaporative Vent Solenoid Valve not working, which would trigger the P0455. A defective Vent Solenoid is pretty common on GM, I have replaced several.

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