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

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 BUICK Description

The Engine Control Module (ECM) monitors the Evaporative Emission System (EVAP) Vent Valve/Solenoid system wiring for opens or shorts.