Yamaha YZ 2018 Series, Owner'S Service Manual

Page: 325 / 402

FUEL INJECTION SYSTEM
8-26
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 illu-
minates 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.
EASB29B339
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. Connect the Yamaha diagnostic tool. Refer to “YAMAHA DIAGNOSTIC TOOL” on page 8-27.
b. Check the fault code number displayed on the Yamaha diagnostic tool.
c. Identify the faulty system with the fault code number.
d. Identify the probable cause of the malfunction.
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2. Check and repair the probable cause of the malfunction.
3. Perform the reinstatement action for the fuel injection system. Refer to “Confirmation of service
completion” in the appropriate table in “TROUBLESHOOTING DETAILS” on page 8-29.
4. After pushing the engine stop switch, push the start switch to check whether the fault code number
is displayed.
TIP
If another fault code number is displayed, repeat steps (1) to (4) until no fault code number is dis-
played.
5. Erase the malfunction history in the diagnostic mode. Refer to “SENSOR OPERATION TABLE”
on page 9-6 (Diagnostic code No.62).
The engine operation is not normal, but the engine trouble warning light does not come on.
1. Check the operation of the following sensors and actuators in the diagnostic mode. Refer to
“TROUBLESHOOTING DETAILS” on page 8-29.
If a malfunction is detected in the sensors or actuators, repair or replace all faulty parts.
If no malfunction is detected in the sensors and actuators, check and repair the inner parts of the
engine.
Fault code No. No fault code No.
Check and repair. Refer to “TROUBLESHOOT-
ING DETAILS” on page 8-29.
Monitor the operation of the sensors and actua-
tors in the diagnostic mode. Refer to “TROU-
BLESHOOTING DETAILS” on page 8-29 and
“LIST OF SELF-DIAGNOSTIC AND FAIL-SAFE
ACTIONS” on page 9-5. Check and repair.
01: Throttle position sensor signal (throttle angle)
30: Ignition coil
36: Injector