P0449

CIRCUIT DESCRIPTION
An ignition voltage is supplied directly to the Evaporative Emission (EVAP) canister vent valve. The Powertrain Control Module (PCM) controls the EVAP vent valve by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the controlled component. The PCM monitors the status of the driver. If the PCM detects an incorrect voltage for the commanded state of the driver, DTC P0449 sets

CONDITIONS FOR RUNNING THE DTC
^ The engine speed is more than 400 RPM.
^ The system voltage is between 6-18 volts.

CONDITIONS FOR SETTING THE DTC
^ The PCM detects that the commanded state of the driver and the actual state of the control circuit do not match.
^ The above conditions are present for a minimum of 5 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ First failure:
- The MIL is not turned ON.
- A DTC is stored in memory under Failed Last Test.
- The Failure Records are stored.
^ Second consecutive drive cycle with a failure:
- The MIL is turned ON.
- A DTC is stored in memory under history.
- The Freeze Frame data is stored.
- The Failure Records are stored.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the malfunction indicator lamp (MIL) after the third consecutive trip the diagnostic has run and passed.
^ The history DTC will clear if the fault conditions have not been detected for 40 warm-up cycles.
^ A scan tool can be used to clear DTC information.

TEST DESCRIPTION

Steps 1-3:

Steps 4-15:

The numbers below refer to the step numbers on the diagnostic table.
2. Listen for a click when the valve operates. Be sure that both the ON and the OFF states are commanded. Repeat the commands as necessary.
5. This step verifies that the PCM is providing ground to the EVAP vent valve.
6. This step tests if the EVAP vent valve control circuit is grounded.