GF07.61-P-3018MAR ME-SFI Safety Fuel Shutoff, Function

GF07.61-P-3018MAR ME-SFI Safety Fuel Shutoff, Function
- refinement package
- as of model year 09


Function requirements for safety fuel shutoff, general points
^ Circuit 87M ON (engine control ON)
^ Engine running

Safety fuel shutoff, general points
To ensure traffic and passenger safety, safety fuel shutoff is applied. The ME-SFI control unit (N3/10) controls the safety fuel shutoff according to the following sensors and signals:
- Crankshaft Hall sensor (B70), motor speed
- Front and rear throttle valve actuators (M16/3, M16/4), throttle valve positions
- Restraint systems control unit (N2/7), direct crash signal
- Restraint systems control unit, crash signal over the engine compartment CAN (CAN C)

Safety fuel shutoff function sequence
The safety fuel shutoff is activated by the ME-SFI control unit in the following conditions:
^ Mechanical fault function sequence in front or rear throttle valve actuator
^ Function sequence error in engine speed signal (TN)
^ Crash signal function sequence

Mechanical fault function sequence in front or rear throttle valve actuator
If the ME-SFI control unit detects a mechanical fault in the front or rear throttle valve actuator by evaluating the throttle valve positions, both throttle valve actuators are switched off. The motor speed is limited to about 1400 rpm in idle and 1800 rpm when driving by switching off the fuel injection valves (Y62).
The ME-SFI control unit detects engine rpm through the signal from the crankshaft Hall sensor.

Function sequence error in engine speed signal (TN)
If the engine speed signal generated by the ME-SFI control unit fails, the fuel pump control unit (N118) switches off the fuel pump (M3)

Crash signal function sequence
If the ME-SFI control unit receives a crash signal directly or indirectly from the restraint systems control unit over the engine compartment CAN, it switches off the fuel pump through the fuel pump control unit and briefly actuates the fuel injection valves in order to depressurize the fuel system.