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?
Replacing the gas cap on 2006 Buick Terraza
by koolkristi in Houston, TX on April 01, 2011
ANSWER by dandd , April 01, 2011
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. here are some shops: https://repairpal.com/directory?address=77053&car_brand_names=Buick