Ignition On, Function - GF07.10-D-1000TSB

Engine 274 in model 907 

Block diagram 

Function requirements for ignition ON, general points 

• Chassis 30

Ignition ON, general points 

At ignition ON, the engine management in the ME-SFI [ME] control unit (N3/36) 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 (EZS) (N73/8) forwards the on-board electrical system voltage from "circuit 30" to "circuit 15" via the interior CAN (CAN B), SAM control unit (N10) and via circuit 15 relay 1 (F152kA).

The "circuit 15 ON" signal is sent redundantly from the EZS control unit via the suspension FlexRay (Flex E) to the powertrain control unit (N127) and via the drive train CAN (CAN C) as well as via the drive train CAN (CAN C1) to the ME-SFI [ME] control unit.

The circuit 15 relay passes the on-board electrical system voltage from "circuit 30" onto "circuit 15".

This causes the relay to close its power contact and, depending on the electrical fuses, the "circuit 30" voltage is passed on to the ME-SFI [ME] control unit and to the engine management sensors and actuators.

The ground connection "circuit 31" is made by the on-board electrical system battery (G1) via the battery ground point (W10).

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

• In order to completely fill the low-pressure fuel circuit, the fuel pump with fill level sensor (M36) is actuated directly via the fuel system control unit (N1189), and the fuel system control unit is actuated via the drive train CAN (only the first time the ignition is switched ON after the vehicle is unlocked).
• In the instrument cluster (A1) the engine diagnosis indicator lamp (A1e58) is actuated via the drive train CAN, the powertrain control unit, the suspension FlexRay, the EZS control unit and the user interface CAN (CAN HMI) for checking purposes.
• The throttle valve actuator (M16/50) checks its return spring (via the position of the throttle valve) and adjusts the position of the actuator, if necessary.
• The fault memory in the ME-SFI [ME] control unit (N3/36) can be read out and deleted via the diagnostic connector (X11/4). The diagnostic connector is connected to the ME-SFI [ME] control unit via diagnostic CAN (CAN D), EZS control unit, suspension FlexRay, powertrain control unit and drive train CAN.