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

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.

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.

DTC P0443 is a Type B DTC.

DTC P0443 is a Type B DTC.

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Electrical Information Reference

Scan Tool Reference

Control Module References

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.

1. Ignition OFF, disconnect the harness connector at the Q12 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 Q12 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 K20 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 K20 ECM.

5. If all circuits test normal, replace the Q12 EVAP canister purge solenoid valve.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.