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 on 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
Illumination of the Check Engine Light can be caused by a loose or worn gas cap.