Troubleshooting Method - Yamaha WR450F 2021 Owner's Service Manual

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.
EAM30353

TROUBLESHOOTING METHOD

The engine operation is not normal and the engine trouble warning light comes on.
1. Check:
• Fault code number
a. Connect the Yamaha diagnostic tool. Refer to "YAMAHA DIAGNOSTIC TOOL" on page 8-31.
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.
2. Check and repair the probable cause of the malfunction.
Fault code No.
Check and repair. Refer to "TROUBLESHOOTING
DETAILS (FAULT CODE)" on page 8-33.
Monitor the operation of the sensors and actuators in
the diagnostic mode. Refer to "TROUBLESHOOT-
ING DETAILS (FAULT CODE)" on page 8-33 and
"SELF-DIAGNOSTIC FUNCTION AND DIAGNOS-
TIC CODE TABLE" on page 9-12.
3. Perform the reinstatement action for the fuel injection system. Refer to "Confirmation of service com-
pletion" in the appropriate table in "TROUBLESHOOTING DETAILS (FAULT CODE)" on page 8-33.
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 displayed.
5. Erase the malfunction history in the diagnostic mode. Refer to "DIAGNOSTIC CODE: SENSOR OP-
ERATION TABLE" on page 9-12 (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 "TROU-
BLESHOOTING DETAILS (FAULT CODE)" on page 8-33.
01: Throttle position sensor signal (throttle angle)
30: Ignition coil
36: Injector
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.
FUEL INJECTION SYSTEM
No fault code No.
Check and repair.
8-30