Question

what causes a P0449 code on a 1999 Chevrolet Silverado 1500?

Answer 1

Hi there,

This code is caused by a faulty vent control valve. This is located under the truck and mounted to the frame next to the charcal canister. It can be tested once off by supplying power and ground to the valve pins.

Answer 2

P0449 CHEVROLET - Evaporative Emission Vent Valve Solenoid Malfunction

Read more: https://www.autocodes.com/p0449_chevrolet.html