Yamaha YZF-R1S Service Manual - page 367
7-23
FUEL INJECTION SYSTEM
FI
Fault code No.
21
Symptom
Open or short circuit is detected from the coolant temperature sensor.
Used diagnostic code No. 06 (coolant temperature sensor)
Order
Inspection operation item and probable
cause
Operation item and countermeasure
Reinstatement
method
1
Connected condition of connector
Inspect 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.
Coolant temperature sensor coupler
Main wiring harness ECU coupler
Sub-wire harness coupler
Reinstated by
turning the
main switch
ON.
2
Open or short circuit in wiring harness
and / or sub lead.
Repair or replace if there is an open or short
circuit.
Between sensor coupler and ECU coupler
Black / Blue – Black / Blue
Green / White – Green / White
3
Defective coolant temperature sensor.
Execute the diagnostic mode (Code No.06).
Replace if defective.
Refer to “COOLING SYSTEM” in chapter 8.