DTC P043F-00: EVAP System Leak Detection Reference Orifice High Flow: General Description

An ELCM, consists of a vacuum pump, an absolute pressure sensor, a reference orifice and a change-over valve (COV), are installed to monitor the evaporation gas leakage.

During ELCM leak detection execution, 5 hours after the ignition switch turned OFF (engine stop), the vacuum pump is turned on. With the pump on, vacuum is drawn across the reference orifice and the ensuing vacuum level becomes the threshold for pass/fail criteria. Once the reference is established, it is time to perform the actual evaporative leak testing.