Ignition On, Function - GF07.10-P-1000MML
Engine 157.9, 276.8, 278.9 in model 217, 222 (except 222.163/173)
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
Upon switching on the ignition the engine compartment terminal 15 relay (K40/8kG) is switched on by the electronic ignition lock control unit (N73) via the interior CAN (CAN B).
The "Circuit 15 ON" signal is sent redundantly over the suspension FlexRay (Flex E) to the powertrain control unit (N127) and over the drive train CAN (CAN C1) to the ME-SFI [ME] control unit. The engine compartment circuit 15 relay forwards the on-board electrical system voltage from "circuit 30" to "circuit 15".
If a voltage is applied to the ME-SFI [ME] control unit at "circuit 15", the engine circuit relay 87M (K40/8kN) 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 87M", the engine management is switched on and an output stage driver in the ME-SFI [ME] control unit takes over actuation of the engine circuit relay 87M.
The "circuit 31" ground connection is made by the on-board electrical system battery (G1) over the battery ground point (W10) and over a number of ground lines to the ME-SFI [ME]/CDI control unit (W25) ground point.
When the engine management is switched on, the ME-SFI [ME] control unit carries out the following functions:
- To ensure that the fuel system is filled entirely, the fuel pump (M3) is actuated directly via the fuel system control unit (N118) and the fuel system control unit is additionally actuated via the drive train CAN (only with the first time ignition ON after unlocking the vehicle).
- In the instrument cluster (A1) the engine diagnosis symbol is actuated for a symbol check via the drive train CAN, powertrain control unit, suspension FlexRay, electronic ignition lock control unit, and user interface CAN (CAN HMI).
- The throttle valve actuator (M16/6) checks its return spring (by the position of the throttle valve) and adapts the position of the actuator, if necessary.
- 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 to the electronic ignition lock control unit via the diagnostic CAN (CAN D) to the powertrain control unit via the chassis FlexRay and to the ME-SFI [ME] control unit via the drive train CAN.
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 (R esearch-O ctane N umber))
- 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
| Electrical function schematic, ignition ON | PE07.10-P-2700-97SED | ||
| Overview of system components for gasoline injection and ignition system with direct injection | Engine 276.8 in model 217, 222 (except 222.163/173) | GF07.70-P-9998MMT | |
| Engine 157.9, 278.9 in model 217, 222 | GF07.70-P-9998MML |