Yamaha Wolverine YX70EPNG, Service Manual

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FUEL INJECTION SYSTEM
9-37
EBS30278
ECU SELF-DIAGNOSTIC FUNCTION
The ECU is equipped with a self-diagnostic function in order to ensure that the fuel injection system is
operating normally. If this function detects a malfunction in the system, it immediately operates the en-
gine 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, a fault code is
stored in the memory of the ECU.
• To inform the rider that the fuel injection system is not functioning, the engine trouble warning light
comes on when the main switch is being turned to start the engine.
• If a malfunction is detected in the system by the self-diagnostic function, the ECU provides an appro-
priate substitute characteristic operation, and alerts the rider of the detected malfunction by illuminat-
ing the engine trouble warning light.
• After the engine has been stopped, the lowest fault code number appears on the multi-function meter
display. Once a fault code has been displayed, it remains stored in the memory of the ECU until it is
deleted.
Engine trouble warning light indication and fuel injection system operation
* The warning light flashes when any one of the conditions listed below is present and the main switch
is turned to “ ” (start):
Checking for a defective engine trouble warning light bulb
The engine trouble warning light comes on for around 2 seconds after the main switch has been turned
to “
” (on). If the warning light does not come on under these conditions, the warning light (LED) may
be defective.
ECU detects an abnormal signal from a sensor
If the ECU detects an abnormal signal from a sensor while the vehicle is being driven, the ECU illumi-
nates the engine trouble warning light and provides the engine with alternate operating instructions that
are appropriate for the type of malfunction.
When an abnormal signal is received from a sensor, the ECU processes the specified values that are
programmed for each sensor in order to provide the engine with alternate operating instructions that
enable the engine to continue to operate or stop operating, depending on the conditions.
Warning light indication ECU operation Fuel injection operation Vehicle operation
Flashing*
Warning provided when
unable to start engine
Operation stopped Cannot be operated
Remains on Malfunction detected
Operated with substitute
characteristics in accor-
dance with the descrip-
tion of the malfunction
Can or cannot be operat-
ed depending on the fault
code
12: Crankshaft position sensor 39:
Fuel injector
(open or short-circuit)
30:
Lean angle sensor
(latch up detected)
41:
Lean angle sensor
(open or short-circuit)
33: Faulty ignition 50:
ECU internal malfunction
(faulty ECU memory)