GF07.61-P-5001MS | Voltage supply of ME-SFI control unit, function | 29.3.07 |
ENGINE 275.953 in MODEL 216, 221 up to Model Year 8
ENGINE 275.982 in MODEL 216, 221 up to Model Year 8
Voltage supply of ME-SFI control unit (N3/10)
The ME-SFI [ME] control unit is supplied with voltage directly from the on-board electrical system battery (G1) (terminal 30
unfused).
It is fitted in the operating voltage range with short-circuit protection as well as reversed polarity protection.
Engine control voltage supply
If signal "terminal 15 ON" sent from EIS [EZS] control unit (N73) via the CAN data bus it is read in by the ME-SFI [ME] control unit and the engine main relay (engine circuit 87 relay (N10/1kC) is actuated with a ground signal. The engine main relay closes its power contact and the voltage from "terminal 30" is transmitted according to corresponding fuses, such as "circuit. 87 M", to the ME-SFI [ME] control unit. Thus the engine control switches on and an output stage driver in the ME-SFI [ME] control unit takes on further actuation of the engine main relay.
In certain cases voltage is supplied through several pins connected in parallel by means of bridges to relief the electrical connectors.
Cutting out the engine control
If ME-SFI [ME] control unit receives the signal "terminal 15 OFF" from EIS [EZS] control unit, computer run-on is started (dependent on the coolant temperature between 4 and 150 s).
Once the processor run-on is complete, the engine main relay is switched off and engine control is thus isolated from the electrical system.
System tests are conducted by the ME-SFI [ME] control unit during the computer run-on and the fault memory is updated.
Ground connection
Several ground connections (terminal 31) for the ME-SFI [ME] control unit, the ignition output stages and the motor electronics are fitted to the body close to the ME-SFI [ME] control unit.