The electric fuel pump (EKP) and the rail pressure control valve (DRV) are similar in terms of activation.
Both can be energised for only a certain period of time (depends on coolant temperature: characteristic curve) in order to avoid thermal damage due to deficient cooling or useless pumping (EKP) against an inactive high pressure pump with the engine stopped.
Power is applied to the electric fuel pump for a period of 60 seconds when terminal 15 is switched on. The rail pressure control valve is activated at 1 kHz.
On exceeding the minimum speed of 50 rpm, both components are permanently activated until terminal 15 is switched off again.
In the event of a crash, the control unit of the Multiple Restraint System (MRS) generates a signal which is carried by the instrument cluster and CAN telegram to the DDE. This signal results in shutdown of the electric fuel pumps. The pumps cannot be reactivated until the terminal 15 changes state from OFF to ON.