Ignition On, Function - GF07.10-P-1000MMR

ENGINE 157.9, 278.9 in MODEL 166 up to model year 2016 

Function requirements for ignition ON, general points 

• Terminal 30

Ignition ON, general points 

For ignition ON, the engine management in the ME-SFI [ME] control unit (N3/10) is switched on and the engine prepared for starting.

Function sequence for ignition ON 

When the ignition is switched on the electronic ignition lock control unit (N73) operating via the interior CAN (CAN B) and the SAM control unit (N10) switch on the circuit 15 relay (F58kR). The signal "circuit 15 ON" is sent redundantly via the chassis CAN 1 (CAN E1) to the ME-SFI [ME] control unit. The circuit 15 relay passes the on-board electrical system voltage from "circuit 30" onto "circuit 15". If a voltage is present at the ME-SFI [ME] control unit at "circuit 15", the engine circuit relay 87M (F58kN) is actuated by means of a ground signal.

This causes the relay to close its power contact and the voltage is forwarded from "circuit 30" (dependent on the respective fuses) as "circuit 87 M4" to the ME-SFI [ME] control unit and as "circuit 87 M1/2/3" to the respective sensors and actuators of the engine management.

If a voltage is present at "circuit 87 M4", the engine management is switched on and an output stage driver in the ME-SFI [ME] control unit takes over actuation of the circuit relay 87 M.

Ground connection "circuit 31" takes place by the on-board electrical system battery (G1) over the on-board electrical system battery ground point at the front right (W10) and over a number of ground lines to the ground point on the front right for the lamp unit (W2).

When the engine management is switched on, the ME-SFI [ME] control unit carries out the following functions:

• To ensure full flow, the fuel pump (M3) is actuated by the fuel system control unit (N118) (both directly and via the drive train CAN (CAN C)) (only at first time ignition ON after unlocking the vehicle).
• In the IC (A1) the engine diagnosis indicator lamp (A1e58) is actuated via chassis CAN 1 and chassis CAN 2 (CAN E2) for a lamp check.
• Data are exchanged with the electronic ignition lock control unit (circuit 50 signal and drive authorization) via chassis CAN 1.
• The throttle valve actuator (M16/6) checks its return spring (by the position of the throttle valve) and may adjust the position of the actuator.
• The fault memory in the ME-SFI [ME] control unit can be read out and deleted via the diagnostic connector (X11/4). The diagnostic connector is networked via chassis CAN 1 and diagnostic CAN (CAN D) with the ME-SFI [ME] control unit.
• Correction programming or diagnosis can be carried out with the Xentry diagnostics over the diagnostic connector.

Different characteristics maps for the engine management can be stored and activated with the correction programming in the ME-SFI [ME] control unit, such as:

• Ignition map for adaptation to various fuel grades (RON correction (Research-Octane Number))
• Mixture maps for enriching the fuel/air mixture in different operating states
• Basic setting for idle speed
• Idle speed for engaged gear range
• Fault setting conditions for smooth running detection
• Temperature correction for switching fan motor (M4/7) on and off