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 Descriptor

DTC P0443: Evaporative Emission (EVAP) Purge Solenoid Control Circuit

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Ignition 1 Voltage | P0443 | P0443 | -- | --
EVAP Canister Purge Valve Control Circuit | P0443 | P0443 | P0443 | --

### 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 ignition is ON.

• | The ignition voltage is greater than 11 volts.

• | The DTC runs continuously once the above conditions are met.

### Conditions for Setting the DTC

The ECM detects the EVAP purge solenoid control circuit is open, shorted to ground, or shorted to voltage.

### Action Taken When the DTC Sets

DTC P0443 is a Type B DTC.

### Conditions for Clearing the DTC

DTC P0443 is a Type B DTC.

### 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. With a scan tool, command the EVAP Purge Solenoid ON and OFF. You should hear the solenoid click when commanded ON and OFF.
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 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 ground.
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 and OFF. The test lamp should pulse ON and OFF with each command.

⇒ | 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.

### Component Testing

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.

### 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