For 1990-2009 cars

### DTC Descriptor

DTC P0443: Evaporative Emission Control System Purge Control Valve Circuit Malfunction

### Diagnostic Fault Information

Important: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

Circuit | Short to Ground | High Resistance | Open | Short to Voltage
--- | --- | --- | --- | ---
Ignition 1 Voltage - Purge Supply | P0443 | P0443 | P0443 | --
EVAP Purge Solenoid Control | P0443 | P0443 | P0443 | P0443

### Circuit/System Description

An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge solenoid valve. The EVAP canister purge solenoid valve is pulse width modulated (PWM). The scan tool displays the amount of ON time as a percentage. The control module monitors the status of the driver. The engine control module (ECM) controls the EVAP canister purge solenoid valve ON time by grounding the control circuit via an internal switch called a driver. If the ECM detects an incorrect voltage for the commanded state of the driver this DTC sets.

### Conditions for Running the DTC

• | Ignition ON.

• | The system voltage is between 9-18 volts.

• | DTC P0443 runs continuously when the above conditions are met.

### Conditions for Setting the DTC

The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for a minimum of 6 seconds.

### Action Taken when the DTC Sets

DTC P0443 is a Type B DTC.

### Conditions for Clearing the MIL/DTC

DTC P0443 is a Type B DTC.

### Reference Information

#### Schematic Reference

Engine Controls Schematics

#### Connector End View Reference

Component Connector End Views

#### Electrical Information Reference

• | Circuit Testing

• | Troubleshooting with a Test Lamp

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References

### Circuit/System Verification

Ignition ON , engine OFF, you should hear a clicking sound when the EVAP canister purge solenoid valve is commanded to 50 percent with a scan tool. The clicking sound should stop when the EVAP canister purge solenoid valve is commanded to 0 percent. The rate at which the valve cycles should increase when the command state is increased and decrease when the command state is decreased.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EVAP canister purge solenoid valve.
2. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal A 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. Connect a test lamp between the voltage supply circuit terminal A and the control circuit terminal B.
4. Command the EVAP canister purge solenoid valve to 50 percent with a scan tool. The test lamp should respond to the command.

⇒ | 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, replace the canister purge solenoid valve.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Evaporative Emission Canister Purge Solenoid Valve Replacement

• | Control Module References