Starting, function - GF07.10-P-1001MI

ENGINE 272.9 (except 272.982) in MODEL 204.0/2 as of model year 2009 

ENGINE 272.9 (except 272.983) in MODEL 212 

ENGINE 272.9 (except 272.984) in MODEL 207 

ENGINE 272.9 in MODEL 204.9 

ENGINE 273.9 in MODEL 207, 212 

Starting function requirements, general points 

• Circuit 87M ON (engine timing ON)
• Engine OFF
• Drive authorization system 3 (DAS 3) start enable
• Engaged gear range "P" or "N"

Starting, general points 

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

• left and right intake camshaft Hall sensors (B6/4, B6/5), intake camshaft positions for ignition circuit recognition
• left and right exhaust camshaft Hall sensors (B6/6, B6/7), exhaust camshaft positions for ignition circuit recognition
• coolant temperature sensor (B11/4)
• crankshaft Hall sensor (B70), engine speed
• start enable clutch pedal switch (S40/5) (for manual transmission)
• electronic ignition lock control unit (N73), "circuit 50 signal" via the chassis CAN (CAN E)

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

• starter (M1)
• ignition coils (T1)
• injection valves (Y62)
• the fuel system control unit (N118), and thus the fuel pump (M3), directly and via the drive train CAN (CAN C)

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 (vehicles with automatic transmission) 
• Function sequence for start end (vehicles with manual transmission) 

Function sequence for start begin 

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

The ME-SFI [ME] control unit actuates the circuit 50 starter relay (N10/1kM) 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 (vehicles with automatic transmission) 

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.

Function sequence for start end (vehicles with manual transmission) 

On reaching an engine cranking speed of 400 to 700 rpm or upon disappearance of the "circuit 50 signal", the ME-SFI [ME] control unit interrupts negative activation to the circuit 50 starter relay and thus ends the starting procedure.

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

	Electrical function schematic for starting	MODEL 204	PE07.10-P-2701-97FAB
		MODEL 207	PE07.10-P-2701-97EAB
		MODEL 212	PE07.10-P-2701-97DAB
	Overview of system components motor electronics (ME-SFI) fuel injection and ignition system		GF07.61-P-9997MI