Integrity diagnosis
The on-board diagnostics must be able to detect a leak in the purge system corresponding to a hole with diameter 0.5 mm.
For this reason, there is a differential pressure sensor mounted on the fuel pump cover and a shut-off valve for the evaporative emission canister atmospheric connection. With the shut-off valve closed, it must be possible to create and maintain a vacuum in the tank using the EVAP canister purge valve. Otherwise, the system is leading and a fault code will be generated. The diagnosis is run once per driving cycle.
The pressure sensor is supplied with 5V from control module pin 43(A) and grounded from control module pin 32(A). Depending on the difference between the tank pressure and atmospheric pressure, the pressure sensor will apply a proportional voltage on control module pin 11(A).
The shut -off valve is open in zero current state. It is supplied with current from the main relay and is controlled from control module pin 2(B).