P0449

CIRCUIT DESCRIPTION
The Powertrain Control Module (PCM) uses Output Driver Modules (ODMs) in order to control many functions of the engine and the transaxle. The ODMs supply the ground path for the PCM-controlled device when the PCM commands the device ON. Each ODM can control several outputs. Unlike the Quad Driver Modules (QDMs) used in earlier model years, the ODMs can diagnose each output circuit. The PCM monitors the ODMs for circuit conditions that are incorrect for the commanded state of the ODM. If the PCM detects an improper circuit condition in the ODM that controls the Evaporative Emissions (EVAP) vent solenoid, Diagnostic Trouble Code (DTC) P0449 will set.

CONDITIONS FOR RUNNING THE DTC
^ The engine is running.
^ System voltage is between 8-16 volts.

CONDITIONS FOR SETTING THE DTC
The PCM detects a circuit conditions that is incorrect for the commanded state of the ODM that controls the EVAP vent solenoid.

The condition is present for at least 10 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The control module illuminates the Malfunction Indicator Lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
^ The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The control module turns OFF the Malfunction Indicator Lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
^ A current DTC "Last Test Failed" clears when the diagnostic runs and passes.
^ A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
^ Use a scan tool in order to clear the MIL and the DTC.

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 solenoid operates. Ensure that both the ON and the OFF states are commanded. Repeat the commands as necessary.
4. This step tests for voltage at the coil side of the EVAP vent solenoid. The ENG IGN fuse supplies power to the coil side of the EVAP vent solenoid.
5. This step verifies that the PCM is providing ground to the EVAP vent solenoid.
6. This step tests if a ground is constantly being applied to the EVAP vent solenoid.