Ignition ON, function - GF07.10-P-1000OGA

ENGINE 642.8 in MODEL 207 as of 6/1/13 

ENGINE 642.8 in MODEL 212, 218 as of model year 2014 

Function requirements for ignition ON, general points 

• Circuit 15 ON

Ignition ON, general points 

With ignition ON, the engine timing in the CDI control unit (N3/9) 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) forwards the on-board voltage from "circuit 30" to "circuit 15" over the circuit 15 relay (N10/1kJ).

If a voltage is present at the CDI control unit at "circuit 15", the engine circuit 87 relay (N10/1kN) is actuated by means of a ground signal. This causes the relay to close its power contact and the voltage is directed from "circuit 30" (downstream of respective fuses) as "circuit 87 M1" to the CDI control unit and to the corresponding sensors and actuators of the engine timing.

If a voltage is present at "circuit 87M1" the engine timing is switched on and an output stage driver in the CDI control unit applies actuation of the engine circuit 87 relay.

The "circuit 31" ground connection is made from the on-board electrical system battery (G1) over the front right battery ground point (W10) and several ground lines to the right front wheel arch ground point (W3/1).

When the engine timing is switched on, the CDI control unit carries out the following functions:

• For cylinder flooding protection, the fuel pump is actuated directly by the fuel system control unit (N118) and over the drive train CAN (CAN C) (only first time ignition ON after unlocking the vehicle).
• In the instrument cluster (A1) the engine diagnosis indicator lamp (A1e58) is actuated to check the lamp.
• Data are exchanged with the electronic ignition lock control unit (circuit 50 signal and drive authorization) over the chassis CAN 1 (CAN E1)
• Actuation of the glow output stage (N14/3) via drive train LIN (LIN C1). The glow output stage then responds by actuating the glow plugs (R9) on the positive side. The preglow indicator lamp (A1e16) is actuated over chassis CAN 2 (CAN E2).
• The fault memory in the CDI control unit can be read out and cleared via the diagnostic CAN (CAN D) by means of the diagnostic connector (X11/4).
• Diagnosis can be carried out with Xentry Diagnostics through the diagnostic connector.
• 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 messages for actuation of the engine diagnosis indicator lamp and the oil pressure warning lamp are received by the instrument cluster from the CDI control unit over chassis CAN 2, routed by the front SAM control unit with fuse and relay module (N10/1), which receives the message on the chassis CAN 1 from the CDI control unit.