Motor electronics (ME) ignition system, function - GF07.61-P-3008MOS

ENGINES 275.953 in MODEL 216.376, 221.176 as of Model Year 09 /AEJ 08

ENGINES 275.982 in MODEL 216.379, 221.179 as of Model Year 09 /AEJ 08

Function requirements for the ignition system, general points

Circuit 87M ON (engine control ON)

Ignition system, general points

Each cylinder has two spark plugs (R4). These are supplied with ignition voltage by the ECI ignition modules of the RH and LH cylinder banks (N92/1, N92/2). For the ignition system, the ME-SFI (N3/10) control unit reads the following sensors and signals:

Front and rear knock sensor (left engine side) (A29/1, A29/2)
Front and rear knock sensor (right engine side) (A30/1, A30/2)
Camshaft Hall sensor, right cylinder bank (B6/3)
Coolant temperature sensor (B11/4)
Charge air temperature sensor (B17/8) and pressure sensor downstream of throttle valve actuator (B28/7), engine load
Crankshaft position sensor (L5), engine speed and crankshaft position

The requirements of the engine torque requirement function are also taken into account.

For the following partial functions, ignition angle adjustment in the direction "retarded" or "advanced" takes place:

Idle speed control
Overheating / knock protection Inertia fuel shutoff
Transmission overload protection Knock sensor system
Engine torque request

Ignition system function sequence

At the ignition firing point, the ME-SFI control unit (N3/10) interrupts the primary circuit of the related cylinder at the ground end (at tml. 1) and thus actuates the output stages in the ECI ignition modules of the RH and LH cylinder banks. From the AC voltage, the output stages generate the ignition voltage for each spark plug.

Determination of the ignition angle takes place dependent on a performance map according to the input signals from the ME-SFI [ME] control unit.

Cylinder arrangement and ignition firing order

Diagnosis

The ignition angles can be checked only with the Diagnosis Assistance System (DAS).

Fig 1: Identifying Cylinder Arrangement And Ignition Firing Order

Courtesy of MERCEDES-BENZ USA

Electrical function schematic for ignition system	Model 216	PE15.12-P-2050-97CAA
Electrical function schematic for ignition system	Model 221	PE15.12-P-2050-97SAA
ME-SFI [ME] control unit, component description	N3/10	GF07.61-P-6000MOS