Possible causes

– Faulty Vacuum Pump Module
– Vacuum Pump Module harness is open or shorted
– Vacuum Pump Module circuit poor electrical connection.
– Faulty Engine Control Module (ECM)

When is the code detected?

To determine leak criterion (Reference pressure), vacuum pump creates negative pressure in canister pump module through 0.02 inch orifice and pressure is measured. If the conditions are not met, Engine Control Module (ECM) the code will be set.

Symptoms

– Engine Light ON (or Service Engine Soon Warning Light)

P043F LEXUS Description

5 hours after the ignition switch is turned OFF, the electric vacuum pump creates negative pressure (vacuum) in the EVAP (Evaporative Emission) system. The Engine Control Module (ECM) monitors for leaks and actuator malfunctions based on the EVAP pressure.