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 provide 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 1 Voltage | 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. If the ECM detects the control circuit voltage is within a predetermined range when the circuit is commanded OFF, this DTC sets.

### Conditions for Running the DTC

• | The ignition is ON or the engine is operating.

• | The ignition 1 voltage is between 10-16 volts.

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

### Conditions for Setting the DTC

#### P0443

The ECM detects the voltage on the EVAP canister purge valve control is between 4-98 percent when the driver is commanded OFF for more than 5 seconds.

#### P0458

The ECM detects the EVAP purge solenoid control circuit is open for more than 5 seconds.

#### P0459

The ECM detects the EVAP purge solenoid control circuit is shorted to ground or voltage for more than 5 seconds.

### Action Taken When the DTC Sets

DTCs P0443, P0458 and P0459 are Type A DTCs.

### Conditions for Clearing the DTC

DTCs P0443, P0458 and P0459 are Type A DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

• | Engine Control Module Connector End Views

• | Engine Controls 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

• | Scan Tool Data List

• | Scan Tool Data Definitions

• | Scan Tool Output Controls

### Circuit/System Verification

1. Ignition ON, command the EVAP purge solenoid ON with a scan tool. You should hear and feel 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 List.

### Circuit/System Testing

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

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

3. Connect a test lamp between the control circuit and the ignition 1 voltage circuit.
4. 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 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. 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 24-28 ohms of resistance between the control circuit terminal and the ignition 1 voltage circuit terminal.

⇒ | If 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 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