Leak Detection Pump: Description and Operation

EVAP VACUUM LEAK PUMP ASSEMBLY

EVAP Vacuum Leak Pump Assembly:

The EVAP vacuum leak pump assembly contains the fuel tank pressure (FTP) sensor, the canister vent solenoid, and an electric motor driven vacuum pump. The vacuum pump provides pressure for leak testing when the engine has been OFF for approximately five hours. The pump assembly also has several internal filters and a 0.5 mm (0.020 inch) reference orifice. The reference orifice provides controlled movement of the pressure within the system, enabling the FTP sensor to accurately monitor system performance. The complete pump assembly is mounted on the EVAP canister, eliminating the need for additional hoses or lines for connections.

EVAP VACUUM LEAK PUMP

The vacuum pump is driven by a 12 volt brush less motor that is high side controlled by the PCM. The pump is a vane type design capable of producing at least 33.50 mm Hg (18 in H2O) of vacuum pressure.