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 Descriptor

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

### 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 control module controls the EVAP canister purge solenoid valve ON time by grounding the control circuit via an internal switch called a driver.

### Conditions for Running the DTC

• | Ignition ON.

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

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

### Conditions for Setting the DTC

• | The control module detects that the commanded state of the driver and the actual state of the control circuit do not match.

• | It occurs 25 times during the 10 tests.

### 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

• | 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

• | Engine Control Module Scan Tool Information

### Circuit/System Verification

With the engine OFF, turn the ignition ON, you should hear a clicking sound when the EVAP canister purge solenoid valve is commanded to 50% with a scan tool. The clicking sound should stop when the EVAP canister purge solenoid valve is commanded to 0%. The rate at which the valve cycles should increase as the commanded state is increased and decreased as the commanded 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 the test lamp illuminates between the supply voltage circuit terminal A and ground.

⇒ | If the circuit tests normal and the supply circuit fuse is open, test or replace the EVAP canister purge solenoid.

3. Connect a test lamp between the supply circuit terminal A and the control circuit terminal B.
4. With a scan tool, the commanded solenoid valve duty is 50, the test lamp should flash or illuminate when commanded to 50 percent and turn OFF when commanded to 0 percent.

⇒ | If the test lamp remains illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the control module.

⇒ | If test lamp remains OFF, test the control circuit for a short to voltage, or an open or high resistance. If the circuit tests normal, replace the control module.

5. If all circuits test normal, replace the EVAP canister purge solenoid valve.

### 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