P0443

CIRCUIT DESCRIPTION
An ignition voltage is supplied directly to the Evaporative Emission (EVAP) purge valve. The EVAP purge valve is Pulse Width Modulated (PWM). The Powertrain Control Module (PCM) controls the EVAP purge valve ON time by grounding the control circuit via an internal switch called a driver. The scan tool displays the amount of ON time as a percentage. The PCM monitors the status of the driver. If the PCM detects an incorrect voltage for the commanded state of the driver, DTC P0443 sets.

CONDITIONS FOR RUNNING THE DTC
^ The engine speed is more than 400 RPM.
^ The system voltage is between 6.0-18.0 volts.

CONDITIONS FOR SETTING THE DTC
^ The PCM 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 PCM will illuminate the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the diagnostic test ran and failed.
^ The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic ran and passed.
^ The History DTC will clear after 40 consecutive warm-up cycles without a malfunction.
^ The DTC can be cleared with a scan tool.

TEST DESCRIPTION

Steps 1-4:

Steps 5-15:

The numbers below refer to the step numbers on the diagnostic table.
2. This step tests if the concern is active. The EVAP purge valve is Pulse Width Modulated (PWM). Clicking should be heard or felt when the purge valve is commanded to 50 percent and should stop when the EVAP purge valve is commanded to 0 percent. The rate at which the valve cycles should increase as the commanded state is increased and decrease as the commanded state is decreased. Repeat the commands as necessary.
5. This step verifies that the PCM is providing ground to the EVAP purge valve.
6. This step tests if a ground is constantly being applied to the EVAP purge valve.