P0443

CIRCUIT DESCRIPTION
An ignition voltage is supplied directly to the evaporative emission (EVAP) canister purge valve. The EVAP canister purge 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 valve ON time by grounding the control circuit via an internal switch called a driver. If the control module detects an incorrect voltage for the commanded state of the driver, this DTC sets.

CONDITIONS FOR RUNNING THE DTC
- The engine speed is more than 400 RPM.
- The system voltage is between 6-18 volts.

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.
- The above conditions are present for a minimum of 5 seconds.

ACTION TAKEN WHEN THE DTC SETS
- The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails.
- The control module records the operating conditions at the time the diagnostic fails. The first time the diagnostic fails, the control module stores this information in the Failure Records. If the diagnostic reports a failure on the second consecutive ignition cycle, the control module records the operating conditions at the time of the failure. The control module writes the operating conditions to the Freeze Frame and updates the Failure Records.

CONDITIONS FOR CLEARING THE MIL/DTC
- The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail.
- A current DTC, Last Test Failed, clears when the diagnostic runs and passes.
- A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic.
- Clear the MIL and the DTC with a scan tool.

TEST DESCRIPTION

Steps 1-2:

Steps 3-6:

Steps 7-13:

Steps 14-15:

The numbers below refer to the step numbers on the diagnostic table.
2. This step tests if the concern is active. The evaporative emission (EVAP) purge solenoid is pulse width module (PWM). You should hear a clicking sound when the purge solenoid is commanded to 50 percent. The clicking sound should stop when the EVAP purge solenoid is commanded to 0 percent. The rate at which the valve cycles should increase when the commanded state is increased, and decrease when the commanded state is decreased. Repeat the commands as necessary.
5. This step verifies that the control module is providing ground to the EVAP purge solenoid.
6. This step tests if a ground is constantly being applied to the EVAP purge solenoid.