The evaporative emission (EVAP) canister purge valve is used to purge fuel vapor from the EVAP canister to the intake manifold. The EVAP canister purge valve is pulse width modulated (PWM). Ignition voltage is supplied directly to the EVAP canister purge valve. The engine control module (ECM) controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.

P0444

The ECM detects the EVAP purge solenoid control circuit is open.

P0445

The ECM detects the EVAP purge solenoid control circuit is shorted to ground or voltage.

DTC P0444 and P0445 are Type B DTCs.

DTC P0444 and P0445 are Type B DTCs.

Schematic Reference

Engine Controls Schematics

Description and Operation

Evaporative Emission Control System Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, command the EVAP purge solenoid ON with a scan tool. You should hear an audible click for about 3-5 seconds.
2. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.

1. Ignition OFF, disconnect the harness connector at the EVAP purge solenoid.
2. Ignition ON, verify that a test lamp illuminates between the ignition 1 voltage circuit terminal 2 and ground.

⇒	If the test lamp does not illuminate, test the ignition 1 voltage circuit for a short to ground or an open/high resistance. If the circuit tests normal and the ignition 1 voltage circuit fuse is open, test all components connected to the ignition 1 voltage circuit and replace as necessary.

3. Connect a test lamp between the control circuit terminal 1 and the ignition 1 voltage circuit terminal 2.
4. Command the EVAP purge solenoid ON with a scan tool. The test lamp should turn ON and OFF for 3-5 seconds.

⇒	If the test lamp is always ON, test the control circuit for a short to ground. If circuit tests normal, replace the ECM.

⇒	If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the ECM.

5. If all circuits test normal, test or replace the EVAP purge solenoid.

1. Ignition OFF, disconnect the harness connector at the EVAP purge solenoid.
2. Test for 24-28 ohms of resistance between the control terminal 1 and the ignition 1 voltage terminal 2.

⇒	If not within the specified range, replace the EVAP purge solenoid.

3. Test for infinite resistance between each terminal and the EVAP purge solenoid housing.

⇒	If less than the specified value, replace the EVAP purge solenoid.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.