Starting, Function - GF07.10-P-1001MMY

ENGINE 157.9, 278.9 in MODEL 166 

as of model year 2016 

ENGINE 157.9, 278.9 in MODEL 292 

Starting function requirements, general points 

• Circuit 87M (engine management ON)
• Engine OFF
• Drive authorization system stage 4 start enable (DAS 4)
• Engaged gear range "P" or "N"

Starting, general points 

The ME-SFI [ME] control unit (N3/10) reads in the following signals for starting:

• Left and right intake camshaft Hall sensors (B6/4, B6/5), intake camshaft positions for ignition circuit detection
• Left and right exhaust camshaft Hall sensors (B6/6, B6/7), exhaust camshaft positions for ignition circuit detection
• Coolant temperature sensor (B11/4), coolant temperature
• Crankshaft Hall sensor (B70), engine rpm
• Electronic ignition lock control unit (N73), "circuit 50 signal" via chassis CAN 1 (CAN E1)

The ME-SFI [ME] control unit actuates the following components to start the engine:

• Starter (M1)
• Ignition coils (T1)
• Fuel injectors (Y76)
• The fuel system control unit (N118) directly and via the drive train CAN (CAN C) and thus the fuel pump (M3)

The ME-SFI [ME] control unit coordinates the injection and firing order during starting based on the signals from the crankshaft Hall sensor and the camshaft Hall sensors.

The starter control in the ME-SFI [ME] control unit takes on actuation and cutout of the starter.

Function sequence for start 

The starter control is subdivided into the following points:

• Function sequence for start begin 
• Function sequence for start end 

Function sequence for start begin 

When the ignition key (transmitter key (A8/1)) is moved into the start position, the ME-SFI [ME] control unit receives the "circuit 50 signal" via chassis CAN1 from the electronic ignition lock control unit.

The ME-SFI [ME] control unit actuates the circuit 50 starter relay (F58kM) with a ground signal. The power contact on the starter relay closes and the starter solenoid switch is supplied at "circuit 50" with voltage from "circuit 30".

Function sequence for start end 

Starter control is carried out automatically by the ME-SFI [ME] control unit (touch start). This means that once the start process is initiated, switching off "circuit 50" will have no further influence on the start procedure.

When engine cranking speed has reached 400 to 700 rpm, or after a starting time of 5 to 40 s (dependent on coolant temperature), the ME-SFI [ME] control unit interrupts the negative activation of the circuit 50 starter relay and thus terminates the starting procedure.

The starting procedure can only be aborted by switching off the ignition.

	Electrical function schematic for starting		PE07.10-P-2701-97NBB
	Overview of system components for gasoline injection and ignition system with direct injection		GF07.70-P-9998MNG