Yamaha YZ 2020 Series Owner's Service Manual page 327

Fault code No.
Item
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
1 Delete the fault code.
50
ECU: faulty ECU memory.
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
Confirm that the fault code has
a condition of "Recovered"
using the Yamaha diagnostic
tool, and then delete the fault
code.
8-40
FUEL INJECTION SYSTEM
Start switch to ON (main relay
ON), and then check the condi-
tion 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