Yamaha MTN850-A 2017 Service Manual page 428

Fault code No.
Item
B-3 Connection of ECU coupler.
Check the locking condition of
the coupler.
Disconnect the coupler and
check the pins (bent or broken
terminals and locking condition
of the pins).
B-4 Wire harness continuity.
B-5 Defective relay unit.
B-6 Defective neutral switch.
B-7 Faulty shift drum (neutral detec-
tion area).
P0500, P1500
Rear wheel sensor: no normal signals are received from the
A
rear wheel sensor.
B Neutral switch: open or short circuit is detected.
C Clutch switch: open or short circuit is detected.
Improperly connected  Con-
nect the coupler securely or
replace the wire harness.
Open or short circuit  Replace
the wire harness.
Between relay unit coupler and
ECU coupler.
black/yellow–black/yellow
Between relay unit coupler and
neutral switch coupler.
sky blue–sky blue
Check the relay unit.
Replace if defective.
Refer to "CHECKING THE
RELAY UNIT (DIODE)" on page
8-163.
Check the neutral switch.
Replace if defective.
Refer to "CHECKING THE
SWITCHES" on page 8-153.
Malfunction  Replace the shift
drum.
Refer to "TRANSMISSION" on
page 5-77.
8-71
FUEL INJECTION SYSTEM
Execute the diagnostic mode.
(Code No. 21)
When the transmission is in
neutral: "ON"
When the transmission is in
gear with the clutch lever
released: "OFF"
Correct indication  Go to item
B-9.
Incorrect indication  Go to
item B-4.
Execute the diagnostic mode.
(Code No. 21)
When the transmission is in
neutral: "ON"
When the transmission is in
gear with the clutch lever
released: "OFF"
Correct indication  Go to item
B-9.
Incorrect indication  Go to
item B-5.
Execute the diagnostic mode.
(Code No. 21)
When the transmission is in
neutral: "ON"
When the transmission is in
gear with the clutch lever
released: "OFF"
Correct indication  Go to item
B-9.
Incorrect indication  Go to
item B-6.
Execute the diagnostic mode.
(Code No. 21)
When the transmission is in
neutral: "ON"
When the transmission is in
gear with the clutch lever
released: "OFF"
Correct indication  Go to item
B-9.
Incorrect indication  Go to
item B-7.
Execute the diagnostic mode.
(Code No. 21)
When the transmission is in
neutral: "ON"
When the transmission is in
gear with the clutch lever
released: "OFF"
Correct indication  Go to item
B-9.
Incorrect indication  Go to
item B-8.