P0449
DTC P0449CIRCUIT DESCRIPTION
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. If the control module detects voltage between 4.6-6.6 on the control circuit when the driver is commanded OFF, this DTC sets.
The table illustrates the relationship between the ON and OFF states, and the OPEN or CLOSED states of the EVAP canister vent solenoid valve.
CONDITIONS FOR RUNNING THE DTC
- The engine speed is more than 40 RPM.
- The system voltage is between 7.5-17.3 volts.
CONDITIONS FOR SETTING THE DTC
- The control module detects between 4.6-6.6 volts on the control circuit when the driver is commanded OFF.
- The fault is present for 0.5 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 DTC
- 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 non-emission related diagnostic.
- Clear the DTC with a scan tool.
DIAGNOSTIC AIDS
- EVAP canister vent solenoid resistance is 18-27 ohms
- To locate an intermittent problem, with a scan tool, command the EVAP canister vent solenoid valve ON and OFF with the ignition ON and the engine OFF. Wiggling wires while listening for the EVAP canister vent solenoid valve to sop clicking may locate a shorted valve or the area where a short to voltage in the wiring may exist.
- For intermittent conditions refer to Intermittent Conditions Intermittent Conditions
TEST
