Question

I have the P0449 and P0455 codes on my 2007 Chevrolet Silverado, what's the most common reason for this code?

Answer 1

The most common cause of both codes is the canister vent valve. This usually will stick open and also cause the 455 code you are getting. Replacing the valve will usually resolve the problem.

Answer 2

P0449 CHEVROLET - Evaporative Emission Vent Valve Solenoid Malfunction
Read more: https://www.autocodes.com/p0449_chevrolet.html

P0455 CHEVROLET - Evaporative Emission Control System Leak Detected Gross Leak
Read more: https://www.autocodes.com/p0455_chevrolet.html