Leak diagnosis, functional description: Notes
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The Evaporative emissions system (including fuel tank) is equipped with leak diagnosis capability which will detect if the system is leaking.
The diagnostic function operates by pressurizing the system and is capable of sensing leakage in cases where the source is at least 1 mm in diameter.
During diagnosis, the Leak Detection Pump -V144- builds up a pressure of approx. 30 mbar in the EVAP system. The pump will switch OFF when the correct pressure is obtained. If pressure falls below a certain value, the pump will switch ON again. The On Board Diagnostic (OBD) monitors the time between the switched ON periods and if it is too short, will register a malfunction in the Diagnostic Trouble Code (DTC) memory.