Yamaha YZF-R125 Service Manual page 317

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Fault code No. 21
Diagnostic code No.
Order Item/components and probable
cause
1 Installed condition of coolant tempera-
ture sensor
2 Connected state of connector
• Coolant temperature sensor coupler
• Main wire harness ECU coupler
3 Open or short circuit in wire harness.
4 Defective coolant temperature sensor. • Execute the diagnostic monitor-
Symptom Coolant temperature sensor: open or short circuit detect-
ed.
06 Coolant temperature sensor
FUEL INJECTION SYSTEM
Check or maintenance job
Check the installed area for
looseness or pinching.
• Check the coupler for any pins
that may have pulled out.
• Check the locking condition of
the coupler.
• If there is a malfunction, repair it
and connect it securely.
• Repair or replace if there is an
open or short circuit.
• Between coolant temperature
sensor coupler and ECU cou-
pler.
(gray/black–gray/black)
(green/red–green/red)
ing mode. (Code No.06)
• Replace if defective.
Refer to "CHECKING THE
COOLANT TEMPERATURE
SENSOR" on page 8-73.
8-46
Reinstatement
method
Setting the
main switch to
"ON".