Electrical Feed Pump.
The electric feed pump is located on the clutch unit and is supplied with voltage from the Differential electronic module (DEM).
The pump starts at ignition on and then works up a max. oil pressure of 35 bar. This is to always enable request for full torque. Then the pump is shut off until the pressure has dropped to 50%, then it starts again. If the pump does not reach max. pressure within 15 seconds, it is shut off and is then started again. This is calculated via a current measuring algorithm in the Differential electronic module (DEM). The pump works in intervals so that it is not damaged in case of a malfunction, e. g., leakage, in the system. The time interval that the pump works between depends on the temperature. At normal room temperature the pump runs at approx. 20-30 second intervals.
Four-wheel drive does not function in the event of a fault in the feed pump.
The feed pump can be diagnosed.