Model: 2009 GMC Sierra
Check engine light is illuminated with code P0449 from scan tool (Evaporative Emission Control System Vent Valve/Solenoid Circuit Malfunction).
- The solenoid does not respond to scan tool command.
- The solenoid has power to A-terminal red wire.
- Test light between terminals A and B does not light.
- EVAP vent solenoid was replaced along with white wire from PCM to solenoid; code still appears.
- Gas cap seals properly.
- New wire does not allow test light to illuminate.
Test for a ground signal at the PCM on the white wire while activating the solenoid. If a ground signal is present, the wire has a break in it and needs replaced. If the signal is not present, the PCM module is faulty and needs replaced.
Courtesy of Mitchell1 SureTrack Real Fix.