Yamaha YZ450F Owner's Service Manual page 308

Fault code
Symptom
3 Connection of sub wire har-
ness coupler.
Check the locking condition
of the coupler.
Disconnect the coupler, and
check the pins (for bent or
broken terminals and locking
condition of the pins).
4 Wire harness continuity.
5 Mounted condition of throttle
position sensor.
Check for looseness or
pinching.
Check the mounted condition
for correctness.
6 Applied voltage of throttle po-
sition sensor lead.
7 Defective throttle position
sensor.
8 Faulty ECU
15
Throttle position sensor: open or short circuit detected.
Improperly connected 
Connect the coupler secure-
ly, or repair/replace the sub-
wire harness.
Open or short circuit  Re-
place the wire harness.
Between throttle position
sensor coupler and ECU cou-
pler.
yellow–yellow
blue–blue
black/blue–black/blue
Improperly mounted sensor
 Remount or replace the
sensor.
Refer to "ADJUSTING THE
THROTTLE POSITION SEN-
SOR" on page 7-9.
Check the applied voltage.
(black/blue–blue)
Refer to "CHECKING THE
THROTTLE POSITION SEN-
SOR" on page 8-44.
Location of discon-
nected lead
Disconnected
ground lead
Disconnected out-
put lead
Disconnected
power supply lead
Execute the diagnostic mode.
(Code No. 1)
When the throttle is fully
closed, 11–14 displays.
When the throttle is fully
opened, 109–116 displays.
Incorrect display range 
Replace the throttle position
sensor.
Replace the ECU.
8-18
FUEL INJECTION SYSTEM
Turn "ON" the switch on the
FI diagnostic tool sub-lead.
Fault code No. is not dis-
played  Repair is finished.
Fault code No. is displayed 
Go to next order.
Turn "ON" the switch on the
FI diagnostic tool sub-lead.
Fault code No. is not dis-
played  Repair is finished.
Fault code No. is displayed 
Go to next order.
Turn "ON" the switch on the
FI diagnostic tool sub-lead.
Fault code No. is not dis-
played  Repair is finished.
Fault code No. is displayed 
Go to next order.
Turn "ON" the switch on the
FI diagnostic tool sub-lead.
Fault code No. is not dis-
played  Repair is finished.
Fault code No. is displayed 
Go to next order.
Output
voltage
5 V
0 V
0 V
Turn "ON" the switch on the
FI diagnostic tool sub-lead.
Fault code No. is not dis-
played  Repair is finished.
Fault code No. is displayed 
Go to next order.