Ignition ON, function - GF07.10-P-1000MMC

ENGINES 157.9 in MODEL 216.3, 221.0/1 

ENGINES 278.9 in MODEL 216.3, 221.0/1 

Function requirements for ignition ON, general points 

• Circuit 30

Ignition ON, general points 

For ignition ON, the engine control in the ME-SFI [ME] control (N3/10) 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 (N73) switches on the circuit 15 relay (2)/reserve 1 (changeover contact) (N10/1kD) via the interior CAN (CAN B). The signal "circuit 15 ON" is sent redundantly via the chassis CAN (CAN E) to the ME-SFI [ME] control unit. The circuit 15 relay conducts the electrical system voltage from "circuit 30" to "circuit 15". If a voltage is present at the ME-SFI [ME] control unit at "circuit 15", engine circuit 87 relay (N10/1kC) is actuated by means of a ground signal.

This causes the relay to close its power contact and the voltage is connected from "circuit 30" (depending on the respective fuses) as "circuit 87 M4" to the ME-SFI [ME] control unit and as "circuit 87 M1/2/3" to the respective sensors and actors of the engine control. If a voltage is present at "circuit 87 M4", the engine control is switched on and an output stage driver in the ME-SFI [ME] control unit takes over actuation of the engine circuit 87 relay.

The "circuit 31" ground connection takes place from the on-board electrical system battery (G1) via the battery ground (W10) and over a number of ground lines to the electronic ground (footwell on the left) (W34/1).

When engine control is switched on, the ME-SFI [ME] control unit carries out the following functions:

• In order to provide full security, the fuel pump (M3) is actuated directly over the fuel system control unit (N118) and also by the FSCU via the drive train CAN (CAN I) (only the first time the ignition is switched ON after the vehicle is unlocked).
• In the IC (A1) the engine diagnosis indicator lamp (A1e58) is actuated via the chassis CAN and backbone CAN (CAN F) for a lamp check.
• Data exchange takes place with the EIS control unit (circuit 50 signal and drive authorization) via the chassis CAN. The throttle valve actuator (M16/6) checks its return spring (via the position of the throttle valve) and may lead to a positioner adaptation.
• The fault memory in the ME-SFI [ME] control unit can be read out and deleted through the data link connector (X11/4). The data link connector is networked via the chassis CAN and diagnostic CAN (CAN D) with the ME-SFI [ME] control unit.
• Correction programming or diagnosis can be carried out with the Diagnosis Assistance System (DAS) through the data link connector.

Different performance maps for the engine control can be stored and activated with the correction programming in the ME-SFI [ME] control unit, such as.

• Ignition maps for adapting the various fuel grades (RON correction (R  esearch O  ctane N  umber))
• Mixture maps for enriching the fuel-air mixture in different operating states
• Basic setting for idle speed
• Idle speed for engaged gear range
• Fault setting conditions for smooth running detection
• Temperature correction for switching the engine and air conditioning electric suction fan with integrated control (M4/7) on and off

	Electrical function schematic, ignition ON	Model 216	PE07.10-P-2700-97CAH
		Model 221	PE07.10-P-2700-97SAG
	Overview of system components for gasoline injection and ignition system with direct injection		GF07.70-P-9998MMB