Yamaha WR250F 2016 Owner's Service Manual page 368

Fault code No.
Item
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).
3 Wire harness continuity.
4 Installed condition of crank-
shaft position sensor.
Check for looseness or
pinching.
Check the gap between the
crankshaft position sensor
and the pickup rotor.
5 Defective crankshaft position
sensor.
6 Malfunction in ECU.
12
Crankshaft position sensor: no normal signals are received
from the crankshaft position sensor.
Improperly connected 
Connect the coupler securely
or repair/replace the wire har-
ness.
Open or short circuit  Re-
place the wire harness.
Between the crankshaft posi-
tion sensor coupler and ECU
coupler.
black/blue–black/blue
gray–gray
Improperly installed sensor
 Reinstall or replace the
sensor.
Refer to "GENERATOR AND
STARTER CLUTCH" on
page 6-62.
Check the crankshaft position
sensor.
Refer to "CHECKING THE
CRANKSHAFT POSITION
SENSOR" on page 9-74.
Replace the ECU.
9-36
FUEL INJECTION SYSTEM
Crank the engine.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 3.
Crank the engine.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 4.
Crank the engine.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 5.
Crank the engine.
Fault code number is not dis-
played  Service is finished.
Fault code number is dis-
played  Go to item 6.