Yamaha WR450F 2021 Owner's Service Manual page 349

Fault code No.
Item
6 Delete the fault code.
Fault code No. 50
TIP
Before troubleshooting, disconnect the starter motor lead from the starter relay.
Fault code No.
Item
Fail-safe system
Diagnostic code No.
Diagnostic tool display
Procedure
Probable cause of malfunc-
Item
tion and check
1 Faulty ECU.
Fault code No. 70
TIP
It is not a malfunction.
If the engine is forcibly stopped by leaving idle, the recovered state is recorded by malfunction mode.
Fault code No.
Item
Fail-safe system
Diagnostic code No.
Diagnostic tool display
Procedure
Probable cause of malfunc-
Item
tion and check
46
Vehicle system power supply: normal voltage is not supplied to the
ECU.
Confirm that the fault code has
a condition of "Recovered"
using the Yamaha diagnostic
tool, and then delete the fault
code.
50
ECU: faulty ECU memory.
Unable to start engine
Unable to drive vehicle
—
—
—
Maintenance job
Replace the ECU.
70
Engine forcibly stops when the vehicle is left idling for a long period
of time.
—
Unable to drive vehicle
—
—
—
Maintenance job
8-50
FUEL INJECTION SYSTEM
Confirmation of service com-
pletion
Push the start switch (main
relay ON), and then check the
condition of the fault code using
the malfunction mode of the
Yamaha diagnostic tool.
Check that the fault code num-
ber is not displayed.
Confirmation of service com-
pletion