DTC P0449: EVAP Vent Valve Performance: Description
WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
An ignition voltage is supplied to the Evaporative Emission (EVAP) canister vent valve. The control module grounds the EVAP canister vent valve control circuit to close the valve by means of an internal switch called a driver. The scan tool displays the commanded state of the EVAP canister vent valve as ON or OFF. The control module monitors the status of the driver. If the control module detects an incorrect voltage for the commanded state of the driver, this DTC sets.
The following table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister vent valve.
ON & OFF, OPEN & CLOSED STATES OF EVAP CANISTER VALVES
| Control Module Command | EVAP Canister Purge Valve | EVAP Canister Vent Valve |
|---|---|---|
| On | Open | Closed |
| Off | Close | Open |