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

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

During ELCM leak detection, the reference pressure (threshold pressure) in a fuel tank is first measured 5 hours after the ignition switch has been turned OFF (engine stop). Then, a vacuum pump creates a vacuum inside the tank and compares it with the actual vacuum state, which helps the ELCM determine a leak.