Possible causes
– Vacuum leaks, damaged hoses or improper routing
– EVAP system – Check fuel cap, canister, valves or components
– Faulty purge or vent solenoids
– Check connector and wiring
– Fuel saturated vapor canister
– Failed EVAP vent solenoid
– EVAP system – Check fuel cap, canister, valves or components
– Faulty purge or vent solenoids
– Check connector and wiring
– Fuel saturated vapor canister
– Failed EVAP vent solenoid
Tech notes
Check Engine Light Diag EVAP Codes
User Submitted Video
When is the code detected?
The Engine Control Module (ECM) has determined that a malfunction exists in the electrical circuit for the vent valve/solenoid in the evaporative emission control system.
Symptoms
– Engine Light ON (or Service Engine Soon Warning Light)
P0449 GMC Description
The Engine Control Module (ECM) monitors the Evaporative Emission System (EVAP) Vent Valve/Solenoid system wiring for opens or shorts.
GMC Technical Service Bulletins for P0449 code
2003 GMC SIERRA CLASSIC ENGINE AND ENGINE COOLING:ENGINE
2003 GMC SIERRA CLASSIC ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL
2003 GMC SIERRA CLASSIC FUEL SYSTEM, GASOLINE:STORAGE:TANK ASSEMBLY:FILLER PIPE AND CAP
2004 GMC SIERRA CLASSIC ENGINE AND ENGINE COOLING:ENGINE
2004 GMC SIERRA CLASSIC ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL
2004 GMC SIERRA CLASSIC FUEL SYSTEM, GASOLINE:STORAGE:TANK ASSEMBLY:FILLER PIPE AND CAP
2005 GMC SIERRA CLASSIC ENGINE AND ENGINE COOLING:ENGINE
2005 GMC SIERRA CLASSIC ENGINE AND ENGINE COOLING:EXHAUST SYSTEM:EMISSION CONTROL
2005 GMC SIERRA CLASSIC FUEL SYSTEM, GASOLINE:STORAGE:TANK ASSEMBLY:FILLER PIPE AND CAP
2006 GMC SIERRA CLASSIC ENGINE AND ENGINE COOLING:ENGINE