P0449

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DTC P0449 Evaporative Emission (EVAP) Control System Vent Valve/Solenoid Circuit Malfunction




Circuit Description
The Powertrain Control Module (PCM) controls the Evaporative Emission (EVAP) Canister Vent Solenoid Valve through the use of a control (ground) circuit. If the PCM commands the Vent solenoid but the voltage remains High (12 Volts); or, if the PCM commands the Vent solenoid OFF but the voltage remains Low (0 volts), then DTC P0449 will set. DTC P0449 is a type A code.

Conditions for Setting the DTC
- Ignition voltage is greater than 10 volts.
- Engine run time is greater than 32 seconds.

The above mentioned conditions are met and one of the following two conditions are met for 25 seconds within a 50 seconds test sample:
- PCM senses voltage is High with the EVAP Canister Vent Solenoid commanded ON.
- PCM senses voltage is Low with the EVAP Canister Vent Solenoid commanded OFF.

Action Taken When the DTC Sets
- The PCM will illuminate the Malfunction Indicator Lamp (MIL).
- The PCM will store the conditions that were present when the DTC was set as Freeze Frame and in Failure Records.

Conditions for Clearing the MIL/DTC
- The PCM will turn OFF the MIL after three consecutive trips without a reported failure.
- A History DTC will clear after 40 consecutive trips without a reported failure.
- The DTC can be cleared using the Scan Tool's "Clear Info" function.

Diagnostic Aids
- Poor connections , or a damaged harness - Inspect the harness connectors for: backed-out terminals, improper mating or damaged terminals. Also check for open circuits, shorts to ground, and shorts to voltage.
- The Fuel Pressure Sensor shares a 5 Volt reference with the MAP sensor and TP sensor.

If these codes are also set, it could indicate a problem with the 5 Volt reference circuit or components itself.

The Fuel Pressure Sensor share a ground with the MAP sensor and the TP sensor.