Yamaha YZF-R1, Service Manual

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SELF-DIAGNOSTIC FUNCTION
9-1
EAS20437
SELF-DIAGNOSTIC FUNCTION
EAS33142
GLOSSARY
EAS32858
OUTLINE
The control unit is equipped with a self-diagnostic function in order to ensure that the system is operat-
ing normally. If this function detects a malfunction in the system, it immediately operates the system
under substitute characteristics and illuminates the warning light to alert the rider that a malfunction has
occurred in the system. Once a malfunction has been detected, a DTC is stored in the memory of the
control unit.
EAS32859
CHECKING THE WARNING LIGHT
The warning light comes on after the main switch has been set to “ON”. Refer to the following table for
lighting up time.
If the warning light still comes on, refer to a check item of a troubleshooting of each system, check and
repair it. If the warning light does not come on, the warning light (LED) may be defective.
TIP
• This engine equips self-diagnostic function. It’s controlled delicately for detecting defective and mal-
function of the exhaust emission control system. Therefor, the vehicle modifying, poor maintenance,
and improper using of the vehicle may also become the cause of the MIL come on. These events may
cause the occurrence of the warning light coming on without malfunction.
• Reprogramming of the ECU software.
• Using the electrical accessory which may affect the ECU.
• Using the incorrect specification of spark plug and fuel injector. Using the third party accessories such
as suspension and exhaust system.
• Change of specifications of drive chain, sprocket, wheel and tire.
• Removing or modifying the O
2
sensor, the air induction system, the exhaust system part (catalyst, EX-
UP, etc.).
• Poor maintenance of the drive chain and tire air pressure.
• Incorrect brake pedal height, rear brake dragging.
• Excessive opening and closing of the throttle grip, frequently used of burnout, wheelie and half clutch.
• Air mixture by fuel supply badness.
Word Description
MIL
(Malfunction indicator
light)
MIL is an indicator light that comes on when a control unit determines a malfunc-
tion.
DTC
(Diagnostic trouble
code)
DTC is a code that is saved within a control unit’s memory when the control unit
determines a malfunction.
Current malfunction A DTC for an unrecovered, current malfunction.
Recovered malfunc-
tion
A DTC for a previously determined but now recovered malfunction.
OBD
(On-board diagnos-
tics)
Self-diagnostic system is equipped in a control unit for the emission control sys-
tem.
GST
(Generic scan tool)
Generic diagnostic tool that complies with OBD standards.
YDT
(Yamaha diagnostic
tool)
Diagnostic tool developed especially for Yamaha vehicles.