Fuel Evaporation Valve

Check electrical function:
[D] 300 - The fuel evaporation valve is driven at intervals of one second. The actuation cycles can be felt with the hand.

Check for leaks:
Release hoses from valve, switch on vacuum pump at service tester and connect to valve (8 mm connection) (note arrow indicating direction of flow). Set vacuum to 600 mbar and apply a voltage of 12 V to the valve. Switch off vacuum pump, after 20 sec, the pressure drop must not exceed 50 mbar.
When power is not applied, the fuel evaporation valve is dosed by a non - return valve to a vacuum of 20 mbar.

Check drive phases:
[D] 100 - The valve is driven at idle speed (display: ON or CLOSED) and is therefore closed. As soon as the oxygen control is active and the engine speed is increased, the valve can be observed to open step-by-step (display: OFF or OPEN).
After switching oft the engine, the valve is held closed for 3...5 sec.