Ignition OFF, function - GF07.10-P-1002MMS

ENGINE 157.9 in MODEL 212, 218 as of model year 2014 

ENGINE 278.9 in MODEL 207, 212, 218 as of model year 2014 

Function requirements for ignition OFF, general points 

• Circuit 87M (engine timing ON)
• Circuit 15 ON

Ignition OFF, general points 

With the ignition OFF, first the engine and then the engine timing are switched off in the ME-SFI [ME] control unit (N3/10).

Function sequence for ignition OFF 

For ignition OFF the terminal 15 relay (N10//1kJ) is switched off by the electronic ignition lock control unit (N73) via the interior CAN (CAN B) and by the front SAM control unit with fuse and relay module (N10/1). The signal "circuit 15 ON" is sent redundantly via the chassis CAN 1 (CAN E1) to the ME-SFI [ME] control unit.

If the ME-SFI [ME] control unit receives the "circuit 15 OFF" signal via the circuit 15 relay, the engine is switched off by shutting off the fuel pump (M3), the fuel injectors (Y76) and the ignition coils (T1) are switched off and computer run-on is started.

Computer power-down is determined by the ME-SFI [ME] control unit and lasts about 4 s. It can, however, last for some minutes due to various functions (such as On-Board Diagnosis (OBD), Drive Authorization System (DAs), thermal management).

When the processor power-down is finished, the engine circuit 87 relay (N101) is switched off and the engine timing system is disconnected from the on-board electrical system (switched off).

System tests are conducted by the ME-SFI [ME] control unit during the computer run-on and the fault memory is updated.

The ground connection "circuit 31" is made from the on-board electrical system battery (G1) over the ground point battery at the front right (W10) and a number of ground lines to the ground point for the electronics assemblies compartment on the left (W16/5).

When the ignition is OFF, the ME-SFI [ME] control unit is supplied with power from the on-board electrical system battery via "circuit 30 fused".