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 P0449: Evaporative Emission (EVAP) Vent Solenoid Control Circuit
DTC P0458: Evaporative Emission (EVAP) Purge Solenoid Circuit Low Voltage
DTC P0459: Evaporative Emission (EVAP) Purge Solenoid Circuit High Voltage
DTC P0498: Evaporative Emission (EVAP) Vent Solenoid Circuit Low Voltage
DTC P0499: Evaporative Emission (EVAP) Vent Solenoid Circuit High Voltage

### Diagnostic Fault Information

Circuit | Short to Ground | High Resistance/Open | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition 1 Voltage - Purge Supply | P0443, P0458 | P0443, P0458 | -- | --
Ignition 1 Voltage - Vent Supply | P0449, P0498 | P0449, P0498 | -- | --
EVAP Purge Solenoid Control | P0443, P0458 | P0443, P0458 | P0459 | --
EVAP Vent Solenoid Control | P0449, P0498 | P0449, P0498 | P0499 | --

### Circuit/System Description

An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid valve. The engine control module (ECM) grounds the EVAP canister purge solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. The EVAP canister purge solenoid valve is pulse width modulated (PWM). A scan tool will display the amount of ON time as a percentage.

An ignition voltage is supplied to the EVAP canister vent solenoid valve. The ECM grounds the EVAP canister vent solenoid valve control circuit through an internal switch called a driver. The ECM monitors the status of the driver. A scan tool will display the commanded state of the EVAP canister vent solenoid valve as ON or OFF.

### Conditions for Running the DTC

• | DTCs P0606, P0628, or P0629 are not set.

• | The ignition is ON.

• | The engine is running.

• | The battery voltage is more than 10 volts.

• | The EVAP canister purge solenoid valve is commanded between 8-91 percent.

• | DTCs P0443, P0449, P0458, P0459, P0498, or P0499 run continuously when the above conditions are met.

### Conditions for Setting the DTC

#### P0443

This DTC sets when an open circuit is detected on the EVAP canister purge solenoid valve control circuit for 3 seconds.

#### P0449

This DTC sets when an open circuit is detected on the EVAP canister vent solenoid valve control circuit for 3 seconds.

#### P0458

This DTC sets when a short to ground is detected on the EVAP canister purge solenoid valve control circuit for 3 seconds.

#### P0459

This DTC sets when a short to B+ is detected on the EVAP canister purge solenoid valve control circuit for 3 seconds.

#### P0498

This DTC sets when a short to ground is detected on the EVAP canister vent solenoid valve control circuit for 3 seconds.

#### P0499

This DTC sets when a short to B+ is detected on the EVAP canister vent solenoid valve control circuit for 3 seconds.

### Action Taken When the DTC Sets

DTCs P0443, P0449, P0458, P0459, P0498 and P0499 are Type B DTCs.

### Conditions for Clearing the MIL/DTC

DTCs P0443, P0449, P0458, P0459, P0498 and P0499 are Type B DTCs.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Testing for Intermittent Conditions and Poor Connections

• | Troubleshooting with a Test Lamp

• | 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

Operate the vehicle within the Conditions for Running the DTC. 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 canister purge or vent solenoid valve.
2. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal 1 and ground.

⇒ | If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and the voltage supply circuit fuse is open, test or replace the EVAP canister purge solenoid.

3. Ignition OFF, test for more than 500,000 ohms between the control circuit terminal 2 and ground.

⇒ | If less than the specified range, repair the short to ground. If the circuit tests normal, replace the ECM.

4. Ignition OFF, test for less than 0.3 V between the control circuit terminal 2 and ground.

⇒ | If more than the specified range, repair the short to B+. If the circuit tests normal, replace the ECM.

5. Ignition OFF, disconnect the ECM. Test for less than 5 ohms between the solenoid valve connector terminal 2 and the ECM connector. Terminal X2-58 for the EVAP canister vent solenoid valve, X1-46 for the EVAP canister purge solenoid valve.

⇒ | If more than the specified range, repair the open circuit. If the circuit tests normal, replace the ECM.

### Component Testing

Ignition OFF, disconnect the harness connector at the solenoid. measure for 10-30 ohms between the voltage supply terminal 1 and the control circuit terminal 2.

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

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Evaporative Emission Canister Purge Solenoid Valve Replacement

• | Evaporative Emission Canister Vent Solenoid Valve Replacement

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