Ducati Scrambler 800 - Service manual > Stepper motor

The stepper motor is useful when the engine does not reach a correct temperature.

The stepper motor works on the throttle valve opening/closing.

To remove and refit the stepper motor, refer to chapters "Removing the airbox and throttle body" and "Refitting the airbox and throttle body".

Check for stepper motor correct operation with the diagnosis instrument DDS 2.

Electric injector

To remove/refit the injector, refer to chapters "Removing the throttle body" and "Refitting the throttle body".

Electronic control unit

The engine control unit (1) is an electronic digital microprocessor-based unit.

The ECU control unit (1) controls both the injectors and the coils, thus controlling fuel injection and ignition in accordance with the engine operating conditions detected by the following sensors:

• absolute pressure sensor (measures the barometric pressure);
• air temperature sensor (measures intake air temperature);
• engine temperature sensor (measures the coolant temperature);
• timing/rpm sensor (for engine rotation speed and the position of each cylinder relative to TDC);
• throttle position sensor (measures the throttle opening angle).

The ECU also monitors battery voltage so that it can adjust injector opening time and ignition coil charging time accordingly.

The ECU determines the following values:

• quantity of fuel delivered to each cylinder;
• injector closing time and therefore injection timing relative to the end of the intake stroke for each cylinder;
• spark advance.

Important The maps, which include spark advance values, injection times, crankshaft angle for injector closing and all correction curves as a function of temperature and atmospheric pressure values, are stored in the Flash Eprom of the ECU. The above values are preset by the Manufacturer after testing the motorcycle under different riding conditions. These settings cannot be changed.

REMOVAL/REASSEMBLY

Remove the seat (Removing the seat)

Disconnect connector (2) of the control unit (1). Remove the control unit (1) by sliding it off pins (3).

Refit control unit (1) by engaging it on pins (3), ensuring it is properly in seat. Connect connector (2).

Refit the seat (Refitting the seat).

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