Diagnostic Instructions

DTC Descriptors

DTC P0444: Evaporative Emission (EVAP) Purge Solenoid Control Circuit Open

DTC P0445: Evaporative Emission (EVAP) Purge Solenoid Control Circuit Shorted

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Ignition 1 Voltage	P0445	P0444	--	--
EVAP Canister Purge Valve Control Circuit	P0445	P0444	P0445	--

Circuit/System Description

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.

Conditions for Running the DTC

Conditions for Setting the DTC

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.

Action Taken When the DTC Sets

DTC P0444 and P0445 are Type B DTCs.

Conditions for Clearing the DTC

DTC P0444 and P0445 are Type B DTCs.

Reference Information

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

Circuit/System Verification

1. 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.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EVAP purge solenoid.
2. Ignition ON, test for battery voltage between the ignition 1 voltage circuit terminal 2 and ground.

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

3. Connect a test lamp between the ignition 1 voltage circuit terminal 2 and the control circuit terminal 1.
4. Ignition ON, command the EVAP purge solenoid ON with a scan tool. The test lamp should turn ON and OFF for about 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 test normal, replace the ECM.

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

Component Testing

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

⇒	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 specified value, replace the EVAP purge solenoid.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.