p0449 code
Safety Car
Joined: Dec 2006
Posts: 4,581
Likes: 1,660
From: Pearland / Houston Tx
System Description
P0449
Battery voltage is supplied to the evaporative emission (EVAP) canister vent solenoid valve. The control module grounds the EVAP canister vent solenoid 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 solenoid valve as ON or OFF. The control module monitors the status of the driver.
Conditions for Setting the DTC
The control module detects that the commanded state of the driver and the actual state of the control circuit do not match for a minimum of 5 seconds.
Circuit Testing
1] Ignition OFF, disconnect the harness connector at the EVAP canister vent solenoid valve.
2] Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal A and ground.
- If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the voltage supply circuit fuse is open, test or replace the EVAP canister vent solenoid.
3] Connect a test lamp between the voltage supply circuit terminal A and the control circuit terminal B.
4] Command the solenoid ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between states.
- If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the control module.
- If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the control module.
5] If all circuits test normal, replace the EVAP canister vent solenoid valve.
P0449
Battery voltage is supplied to the evaporative emission (EVAP) canister vent solenoid valve. The control module grounds the EVAP canister vent solenoid 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 solenoid valve as ON or OFF. The control module monitors the status of the driver.
Conditions for Setting the DTC
The control module detects that the commanded state of the driver and the actual state of the control circuit do not match for a minimum of 5 seconds.
Circuit Testing
1] Ignition OFF, disconnect the harness connector at the EVAP canister vent solenoid valve.
2] Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal A and ground.
- If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the voltage supply circuit fuse is open, test or replace the EVAP canister vent solenoid.
3] Connect a test lamp between the voltage supply circuit terminal A and the control circuit terminal B.
4] Command the solenoid ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between states.
- If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the control module.
- If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the control module.
5] If all circuits test normal, replace the EVAP canister vent solenoid valve.
