Yamaha 2002 TDM900 Service Manual page 17

S Ignition control
The ignition control function of the ECU controls the ignition timing and the duration of ignition ener-
gizing. The ignition timing control uses the signals from the throttle position sensor (to detect the angle
of the throttle), and the crankshaft position sensor and speed sensor (to detect the speed of the en-
gine). This control establishes an ignition timing that suits the operating condition of the engine
through compensations made to the basic ignition timing control map. The ignition energizing dura-
tion control establishes the energizing duration to suit the operating conditions by calculating the en-
ergizing duration in accordance with the signal received from the crankshaft position sensor and the
battery voltage.
S Fuel control
The fuel control function of the ECU controls the injection timing and injection duration. The injection
timing control controls the injection timing during the starting of the engine and the injection timing
during the normal operation of the engine, based on the signals received from the crankshaft position
sensor and the cylinder identification sensor. The injection duration control determines the duration of
injection based on the signals received from the atmospheric pressure sensors, temperature sen-
sors, and the position sensors, to which compensations are made to suit various conditions such as
the weather, atmospheric pressure, starting, acceleration, and deceleration.
S Load control
The ECU effects load control in the following manner:
1. Stopping the fuel pump and injectors when the motorcycle overturns
The ECU turns OFF the fuel injection system relay when the lean angle cut-off switch is tripped.
2. Operating the headlight illumination relay
On the model for Europe, the ECU causes the headlight relay 2 to output a constant ON signal,
provided that the main switch is ON. On the model for Australia, the ECU controls the headlight
relay 2 in accordance with the engine speed as required by the daytime illumination specification.
3. Operating the radiator fan motor in accordance with the coolant temperature
The ECU controls the radiator fan motor relay ON/OFF in accordance with the coolant tempera-
ture.
4. Operating the AI system solenoid valve
The ECU controls the energizing of the solenoid valve in accordance with the driving conditions.
5. Operating the intake solenoid valve
The ECU controls the energizing of the solenoid valve in accordance with the driving conditions.
S Self-diagnosis function
The ECU is equipped with a self-diagnosis function to ensure that the engine control system is operat-
ing normally. The ECU mode functions include a diagnosis mode in addition to the normal mode.
Normal mode
S To check for any blown bulbs, this mode illuminates a warning light while the main switch is turned ON,
and while the starter switch is being pressed.
S If the starting disable warning is activated, this mode alerts the rider by blinking the warning light while
the start switch is being pressed.
S If a malfunction occurs in the system, this mode provides an appropriate substitute characteristic op-
eration, and alerts the rider of the malfunction by illuminating a warning light. After the engine is
stopped, this mode displays a fault code on the clock LCD.
Diagnosis mode
S In this mode, a diagnostic code is input into the ECU through the operation of the operating switch on
the meter, and the ECU displays the values output by the sensors or actuates the actuators in accor-
dance with the diagnostic code. Whether the system is operating normally can be checked by observ-
ing the illumination of the warning light, the values displayed on the meter, or the actuating state of the
actuators.
FEATURES
1-6
GEN
INFO