For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### DTC Descriptors

DTC P0443 : Evaporative Emission (EVAP) Purge Solenoid Control Circuit
DTC P0458: Evaporative Emission (EVAP) Purge Solenoid Control Circuit Low Voltage
DTC P0459: Evaporative Emission (EVAP) Purge Solenoid Control Circuit High Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition Voltage | P0443, P0458 | P0443 | -- | --
EVAP Canister Purge Valve Control Circuit | P0458 | P0443 | P0459 | --

### 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

• | The engine speed is greater than 80 RPM.

• | The ignition voltage is between 10-18 volts.

• | The ECM has commanded the EVAP canister purge valve ON and OFF at least once during the ignition cycle.

• | The DTCs run continuously once the above conditions are met.

### Conditions for Setting the DTC

#### P0443

The ECM detects the EVAP canister purge solenoid control circuit is open. The condition exists for 4 seconds or a cumulative of 30 seconds.

#### P0458

The ECM detects the EVAP canister purge solenoid control circuit is shorted to ground. The condition exists for 4 seconds or a cumulative of 30 seconds.

#### P0459

The ECM detects the EVAP canister purge solenoid control circuit is shorted to voltage. The condition exists for 4 seconds or a cumulative of 30 seconds.

### Action Taken When the DTC Sets

DTC P0443, P0458 and P0459 are Type B DTCs.

### Conditions for Clearing the DTC

DTC P0443, P0458 and P0459 are Type B DTCs.

### Diagnostic Aids

If the condition is intermittent, move the related harnesses and connectors, with the engine operating, while monitoring the scan tool EVAP Purge Solenoid Circuit Test Status parameters for the component. A circuit test status parameter changes from OK or Not Run to Fault if there is a condition with the circuit or a connection.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Evaporative Emission Control System Description

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Ignition ON, command the EVAP purge solenoid to 50 percent with a scan tool. You should hear an audible click.
2. Engine operating, observe the scan tool EVAP Purge Solenoid Circuit Test Status parameters. Verify the parameters display OK or Not Run.
3. 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, verify that a test lamp illuminates between the ignition voltage circuit terminal 1 and ground.

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

3. Connect a test lamp between the control circuit terminal 2 and the ignition voltage circuit terminal 1.

Note: The control circuit for the EVAP purge solenoid is pulled-up to voltage within the ECM, 2.6-4.6 volts on the control circuit is normal.

4. Command the EVAP purge solenoid to 50 percent and then to 0 percent with a scan tool. The test lamp should illuminate or flash and then go OFF.

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

5. Test for 2.6-4.6 V between the control circuit terminal 2 and the ECM housing.

⇒ | If the voltage is not within the specified range, replace the ECM.

6. 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. Test for 15-20 Ω between the terminals of the EVAP purge solenoid.

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

2. Measure the resistance between each terminal of the EVAP purge solenoid and the EVAP purge solenoid housing. The DMM should display OL.

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

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Evaporative Emission Canister Purge Solenoid Valve Replacement

• | Control Module References for ECM replacement, setup, and programming