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

Engine 274 in model 447, 448 

except code XM0 (Facelift) 

Function requirements for ignition ON, general points 

• Circuit 15 ON

Ignition ON, general points 

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

Function sequence for ignition ON 

When the ignition is switched on, the electronic ignition lock control unit (EZS) (N73) forwards the on-board electrical system voltage from "circuit 30" to "circuit 15" via the interior CAN (CAN B), SAM control unit (N10/1) and over the engine compartment circuit 15 relay (K40/10kR).

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

This causes the circuit relay 87M (K4010kN) to close its power contact and the voltage is forwarded from "circuit 30" (dependent on the respective fuses as "circuit 87" to the ME-SFI [ME] control unit (N3/34) and to the respective sensors and actuators of the engine management.

If a voltage is present at "circuit 87", the engine management is switched on and an output stage driver in the ME-SFI [ME] control unit (N334) takes over actuation of the engine circuit relay 87M (K40/10kN).

The ground connection "circuit 31" is made over a number of ground lines to the front left ground point for lamp unit (W9).

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

• Actuation of the fuel pump with fill level sensor (M3/6). To do this the MESFI [ME] control unit (N3/34) sends the "fuel pump ON" signal to the FSCU (FSCU) (N118). This signal is sent redundantly from the ME-SFI [ME] control unit (N3/34) as a CAN signal via the drive train CAN (CAN C) and as a direct ground signal. Upon receiving it the FSCU (FSCU) (M3) actuates the fuel pump with fuel pump with a fill level sensor (N118/6) with a direct signal (only for the first ignition ON after unlocking the vehicle)
• Data exchange with the electronic ignition lock control unit (EZS) (N73) occurs via the chassis CAN (CAN E)
• The fault memory in the ME-SFI [ME] control unit (X11/34) can be read out and deleted via the diagnostic connector (N3)
• The diagnostic connector is networked via the diagnostic CAN (CAN D), the electronic ignition lock control unit (EZS) (N73) and the chassis CAN (CAN E) with the ME-MFI [ME] control unit (N3/34)
• The throttle valve actuator (M16/50) check its return spring over the actual value potentiometer 1 (M16/50r1) and the actual value potentiometer 2 (M16/50r2) and performs, if necessary, an adaptation over the throttle valve actuator motor (M16/50m1)

Function sequence for actuation of IC control unit (IC) (A1/1) 

The engine diagnosis indicator lamp (A1/1) in the IC control unit (IC) (A1/1e58) is actuated by the ME-MFI [ME] control unit (N334) via the chassis CAN (CAN E).

	Electrical function schematic, ignition ON	Engine 274 in model 448 except code XM0 (Facelift)	PE07.10-S-2700-97VDC
		Engine 274 in model 447 except code XM0 (Facelift)	PE07.10-S-2700-97TRC
	Overview of system components for gasoline injection and ignition system with direct injection		GF07.70-S-9998TRC