Starting System: Description and Operation

GF15.30-P-3000MIR Starter Control, Function
ENGINE 272.949 in MODEL 230.454 as of Model Year 09 /Modification Year 08 model refinement package
ENGINE 272.968 in MODEL 230.458 as of Model Year 09 /Modification Year 08 model refinement package
ENGINE 273.965 in MODEL 230.471 as of Model Year 09 /Modification Year 08 model refinement package

Function requirements for starter control, general points
^ Circuit 87M ON (engine control ON)
^ Engine OFF
^ Drive authorization system start enable (DAS 3)
^ Engaged gear range "P" or "N"

Starter control, general points
Starter control which is integrated in the ME-SFI [ME] control unit (N3/10) takes over actuation and shutoff of the starter (M1).
The ME-SFI [ME] control unit reads the following sensors and signals for starter control:

- Coolant temperature sensor (B11/4)
- Crankshaft Hall sensor (B70), motor speed
- EIS [EZS] control unit (N73), circuit 50 signal via engine compartment CAN (CAN C)
- Electric controller unit (VGS) (Y3/8), gear range via engine compartment CAN

Starter control function sequence
The function sequence is subdivided into the following steps:

^ Start function sequence
^ End of start function sequence

Start function sequence
The ME-SFI [ME] control unit receives the "circuit 50 signal" from the EIS [EZS] control unit via the engine compartment CAN by actuating the transmitter key (A8/1) in the start position.
It actuates the starter relay (K40/4kL) 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".

End of start function sequence
Start control is carried out automatically by the ME-SFI [ME] control unit (touch start). This means that if the start process is initiated switching off of "circuit 50" has no further influence on the start process.
On reaching an engine cranking speed of 400 to 700 rpm or a starting time of approx. 5 to 40 seconds (depending on the coolant temperature), the ME-SFI [ME] control unit interrupts negative activation to the starter relay and thus ends the starting procedure.

The start sequence can only be aborted by switching off the ignition.