Ignition OFF function - GF07.10-P-1002MI

ENGINES 272.9 (except 272.98) in MODEL 204.0 /2 as of model year 2009 /YoM 08 

ENGINES 272.9 (except 272.98) in MODEL 204.9, 207.3 /4, 212.0 /2 

ENGINES 273.9 in MODEL 207.3 /4, 212.0 /2 

Function requirements ignition OFF, general points 

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

Ignition OFF, general points 

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

Ignition OFF function sequence 

When the ignition is switched off, the electronic ignition lock control unit (N73) switches off relay terminal 15 (N10/1kJ) via chassis CAN (CAN E).

If the ME-SFI [ME] control unit receives the signal "circuit 15 OFF" via the circuit 15 relay, the following components are switched off and the computer shut-off delay is started:

• Fuel pump (M3) over fuel pump control unit (N118)
• Injection valves (Y62)
• Ignition coils (T1)

Computer power-down is determined by the ME-SFI control unit and lasts about 5 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 computer power-down is complete, the engine circuit 87 relay (N10/1kN) is switched off and the engine control is disconnected from the vehicle electrical system (switched off).

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

Ground is connected to "circuit 31" from the vehicle electrical system battery (G1) via the battery ground point at the front right (W10) and over a number of ground lines to the ground point for the electronic assemblies compartment on the left (W16/5). When the ignition is OFF, the ME-SFI [ME] control unit is supplied with power from the vehicle electrical system battery via "circuit 30 fused".