Ignition On, Function - GF07.10-S-1000TRJ

Engine 274 in model 447.6/7 

with code XM0 (Facelift) 

Function requirements for ignition ON, general points 

• Circuit 15 on

Ignition ON, general points 

In case of ignition ON, the engine management in the ME-SFI [ME] control unit (N3/34) is switched on and the engine is prepared for starting.

Function sequence for ignition ON 

With the switching on of the ignition, the on-board electrical system voltage is forwarded from circuit 30 to circuit 15 by the electronic ignition lock control unit (EZS) (N73) and via the circuit 15 relay (K40/10kR).

If a voltage is applied at circuit 15, the circuit 87M relay (K40/10kN) is directly actuated by the ME-SFI [ME] control unit (N3/34) using a ground signal.

The circuit 87M relay (K40/10kN) thus closes its power contact and the voltage of circuit 30 is, according to the corresponding fuses, routed as "circuit 87" to the ME-SFI [ME] control unit (N3/34) and to the corresponding sensors and actuators of the engine management.

If a voltage is applied at circuit 87, the engine management switches on and an output stage driver in the ME-SFI [ME] control unit (N3/34) takes over the further actuation of the circuit 87M relay (K40/10kN).

The "circuit 31" ground connection is realized via several ground lines to the left front lamp unit (W9) ground point.

When the engine management is switched on, the ME-SFI [ME] control unit (N3/34) carries out the following functions:

• Actuation of fuel pump with fuel delivery module (M3/3). For this purpose, the ME-SFI [ME] control unit (N3/34) transmits the "fuel pump ON" signal to the following control units:
  • Fuel system control unit (FSCU) (N118) (Vehicles with code G42 (7G-TRONIC PLUS))
  • Fuel system control unit (FSCU) (N118/9) (Vehicles with code G43 (9G-TRONIC))

  This signal is transmitted redundantly by the ME-SFI [ME] control unit (N3/34) as a CAN signal via the drive CAN (CAN C) and as a direct ground signal. The fuel system control unit (FSCU) then actuates the fuel pump with fuel delivery module (M3/3) with a direct signal (after the unlocking sequence, only during the first switching on of the ignition).

• Data exchange with the electronic ignition lock control unit (EZS) (N73).
• The fault memory in the ME-SFI [ME] control unit (N3/34) can be read out via the diagnostics connection (X11) and cleared.
• The throttle valve actuator (M16/50) checks its return spring via the actual value potentiometer 1 (M16/50r1) and the actual value potentiometer 2 (M16/50r2) and performs, if necessary, an adaptation via the throttle valve actuator motor (M16/50m1).

Function sequence for instrument cluster actuation 

In the instrument cluster control unit (IC) (A1/1), the engine diagnosis indicator lamp (A1/1e58) is actuated by the ME-SFI [ME] control unit (N3/34).

	Function schematic for ignition ON		PE07.10-S-2505-97TRM
	Overview of system components for gasoline injection and ignition system with direct injection		GF07.70-S-9998TRJ