Yamaha YZF-R1S Service Manual page 365

Fault code No. 18
Used diagnostic code 53
Order Inspection operation item and probable
couse
1 Connected condition of connector
Inspect the coupler for any pins that
may have pulled out.
Check the locking condition of the
coupler
2 Open or short circuit in wire harness.
3 Defective EXUP servo motor.
4 Defective EXUP valve, pulley, cable.
FUEL INJECTION SYSTEM
Symptom EXUP servo motor is stuck.
Operation item and countermeasure
If there is a malfunction repair it and
connect it securely.
EXUP servo motor coupler
Main wire harness ECU coupler.
Repair or replace if there is an open
or short circuit.
Between motor coupler and ECU coupler.
Black / Green – Black / Green
Black / Red – Black / Red
Execute the diagnostic mode (Code No.53).
Replace if defective.
1. Disconnect the EXUP cables from the EXUP
servomotor pulley.
2. Disconnect the EXUP servomotor coupler from
the wire harness.
3. Connect the battery leads to the EXUP servo-
motor coupler as shown.
Positive battery terminal ! black/green
Negative battery lead ! black / red
4. Check that the EXUP servomotor pulley ro-
tates several times.
CAUTION:
To prevent damaging the EXUP servomo-
tor, perform this test within a few seconds
of connecting the battery.
5. Does the EXUP servomotor pulley turn?
Replace if defective
7-21
FI
Reinstatement
method
Reinstated by
turning the
main switch
ON.
It takes 120
seconds at the
maximum
before the
original state
returns.
1
2