Yamaha Wolverine YX70EPNG, Service Manual

Page: 422 / 503

FUEL INJECTION SYSTEM
9-47
Fault code No. 21
TIP
If fault code numbers “21” and “37” are both indicated, take the actions specified for fault code number
“21” first.
Fault code No. 16
Item Throttle position sensor: stuck throttle position sensor is detected.
Fail-safe system
Able to start engine
Able to drive vehicle
Diagnostic code No. 01
Indicated
Throttle position sensor signal
• 14–20 (fully closed position)
Procedure Check with throttle valve fully closed.
Item
Probable cause of malfunc-
tion and check
Maintenance job
Confirmation of service com-
pletion
1 Installed condition of throttle po-
sition sensor.
Check for looseness or pinch-
ing. Improperly installed sensor
→
Reinstall or adjust the sensor.
Refer to “ADJUSTING THE
THROTTLE POSITION SEN-
SOR” on page 7-13.
Turn the main switch to “ ”
(on), then press the accelerator
pedal.
Fault code number is not dis-
played
→
Service is finished.
Fault code number is displayed
→
Go to item 2.
2 Defective throttle position sen-
sor. Check throttle position sensor
signal.
Execute the diagnostic mode.
(Code No. 01)
When the throttle valve is fully
closed:
A value of 14–20 is indicated.
An indicated value is out of the
specified range
→
Replace the
throttle position sensor.
Turn the main switch to “ ”
(on), then operate the throttle.
Fault code number is not dis-
played
→
Service is finished.
Fault code number is displayed
→
Go to item 3.
3 Malfunction in ECU. Replace the ECU.
Fault code No. 21
Item Coolant temperature sensor: open or short circuit detected.
Fail-safe system
Able to start engine
Able to drive vehicle
Diagnostic code No. 06
Indicated Displays the coolant temperature.
Procedure
Compare the actually measured coolant temperature with the indicated
value.
Item
Probable cause of malfunc-
tion and check
Maintenance job
Confirmation of service com-
pletion