Yamaha TMAX XP500F 2015, Service Manual, Page: 390 / 478

FUEL INJECTION SYSTEM
8-33
EAS30505
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
number 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
flashes while the ON/start switch “ ” is being pushed 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 odometer LCD. This
number 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 following conditions is present and the ON/start switch
“ ” is pushed:
Checking the engine trouble warning light
The engine trouble warning light comes on for around 2 seconds after the ON/start switch “ ” is
pushed. 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 operating or stop operating, depending on the conditions.
EAS30506
TROUBLESHOOTING METHOD
The engine operation is not normal and the engine trouble warning light comes on.
1. Check:
• Fault code number
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a. Check the fault code number displayed on the meter.
b. Identify the faulty system with the fault code number.
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 33: Ignition coil
19:
Sidestand switch
(open circuit in the wire to the ECU)
41:
Lean angle sensor
(open or short circuit)
30:
Lean angle sensor
(latch up detected)
50:
ECU internal malfunction
(faulty ECU memory)