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

Connector End View Reference

Description and Operation:

Evaporative Emission Control System Description

Electrical Information Reference

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

1. With a scan tool, command the EVAP Purge Solenoid ON. You should hear an audible click for about 3-5 seconds.
2. If the vehicle passes the Circuit/System Verification Test, then operate the vehicle within the conditions for running the DTC. You may also operate the vehicle within the conditions that are captured in the Freeze Frame/Failure Records Data List.

1. Ignition OFF, disconnect the harness connector of the EVAP purge solenoid.

Important: The test lamp is used to load the circuit and may not illuminate.

2. Connect a test lamp between the ignition 1 voltage circuit of the EVAP purge solenoid and the negative terminal of the battery.
3. Ignition oN, load test for battery voltage between the ignition 1 voltage circuit of the EVAP purge solenoid and ground.

⇒	If less than B+, repair the ignition 1 voltage circuit of the EVAP purge solenoid for a short to ground or an open/high resistance.

4. With the ignition OFF, connect a test lamp between the control circuit and the ignition 1 voltage circuit of the EVAP purge solenoid.
5. With the ignition ON, use a scan tool to command the EVAP purge solenoid ON. The test lamp should pulse ON and OFF for about 3-5 seconds.

⇒	If the test lamp remains ON all the time, test for a short to ground on the control circuit. If circuit/connections test normal, replace the ECM.

⇒	If the test lamp remains OFF all the time, test for a short to voltage or an open/high resistance on the control circuit. If circuit/connections test normal, replace the ECM.

6. If all circuits/connections test normal, test or replace the EVAP purge solenoid.

1. Measure for 24-28 ohms of resistance between the terminals of the EVAP purge solenoid.

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

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

⇒	If less than infinite resistance, replace the EVAP purge solenoid.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.