Yamaha XV1700PCR Road Star Warrior, Service Manual

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FI
FUEL INJECTION SYSTEM
ECU’S SELF-DIAGNOSTIC FUNCTION
The ECU is equipped with a self-diagnostic function in order to ensure that the engine control sys-
tem is operating normally. If this function detects a malfunction in the system, it immediately oper-
ates the engine under substitute characteristics and illuminates the engine trouble warning light to
alert the rider that a malfunction has occurred in the system. Once a malfunction has been detected,
it becomes stored in the ECU memory in the form of a fault code.
ECU’s mode function
The ECU is equipped with a diagnosis mode, in addition to the normal mode in which the ECU oper-
ates normally.
Normal mode
• To check whether the warning light bulb is blown, the warning light illuminates for 1.4 seconds
after the main switch has been turned ON, and while the starter switch is being pressed.
• To inform the rider that the fuel injection stop function is active, the warning light blinks while the
start switch is being pressed to start the engine.
• If a malfunction in the system is detected by the self-diagnostic function, this mode provides an
appropriate substitute characteristic operation, and alerts the rider of the detected malfunction by
illuminating a warning light.
• After the engine has been stopped, digital numbers representing the self-diagnostic fault codes
appear on the clock LCD. Once a self-diagnostic fault code has been displayed, it remains stored
in the ECU memory until a deletion operation is performed.
Diagnosis mode
• In this mode, diagnostic codes are input into the ECU in accordance with the number of times the
start switch has been operated.
• In accordance with the diagnostic codes, the ECU displays the values received from the sensors
and actuates the actuators.
• Whether or not the system is operating normally is determined by a human operator through the
observations of the values indicated by the engine trouble warning light or the actuating conditions
of the actuators.