Yamaha WR250F 2016 Owner's Service Manual page 384

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 Malfunction in ECU.
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 Connection of Yamaha diag-
nostic tool coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).
2 Connection of wire harness
ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins).
50
Faulty ECU memory. (When this malfunction is detected in the
ECU, the fault code number might not appear on the meter.)
Unable to start engine
Unable to drive vehicle
—
—
—
Maintenance job
Replace the ECU.
waiting for connection
No communication signal is received from the ECU.
Able to start engine (Unable when ECU is malfunctioning)
Able to drive vehicle (Unable when ECU is malfunctioning)
—
—
—
Maintenance job
Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.
Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.
9-52
FUEL INJECTION SYSTEM
Confirmation of service
completion
Push the start switch.
Check that the fault code
number is not displayed.
Confirmation of service
completion
Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 2.
Push the start switch.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 3.