Yamaha XF50W Service Manual page 263

Fault codeNo. 33
Used diagnostic code No. D30
Inspection operation item and
Order
probable cause
1 1 1 Connected condition of con-
nector
Inspect the coupler for any
pins that may have pulled
out.
Check the locking condition
of the coupler.
2 2 2 Open or short circuit in lead.
3 3 3 Defective ignition coil (test the
primary and secondary coils for
continuity).
Fault code No. 37
Used diagnostic code No. D54 (ISC (idle speed control) valve)
Inspection operation item and
Order
probable cause
1 1 1 1 Incorrect speed sensor signal
2 2 2 2 Throttle valve does not fully
close
ISC (idle speed control) valve
stuck fully open
3 3 3 3
ISC (idle speed control) valve
not moving correctly
4 4 4 4
FUEL INJECTION SYSTEM
Symptom Open circuit detected in the primary lead of the ignition coil.
Operation item and countermeasure
If there is a malfunction, repair it and connect
it securely.
Ignition coil primary side coupler - orange
Main wiring harness ECU coupler
Repair or replace if there is an open or short
circuit.
Between ignition coil coupler and ECU cou-
pler/main harness
orange - orange
Execute the diagnostic mode (code No. D30)
Replace if defective.
Refer to "IGNITION SYSTEM" in chapter 8.
Symptom
Operation item and countermeasure
Check the speed sensor.
Check the speed sensor leads.
Check the speed sensor coupler.
Check the throttle body.
Refer to "THROTTLE BODY ASSEMBLY AND
FUEL INJECTOR ASSEMBLY" .
Check the throttle cables.
Refer to "ADJUSTING THE THROTTLE
CABLE FREE PLAY" in chapter 3.
The ISC (idle speed control) valve is stuck
fully open if it does not operate when the main
switch is set to OFF.
(Touch the ISC (idle speed control) valve unit
with your hand and check if it is vibrating to
confirm if the ISC (idle speed control) valve
is operating.)
NOTE:
Do not remove the ISC (idle speed control)
valve unit.
Execute the diagnostic mode (code No. D54)
After the ISC (idle speed control) valve is fully
closed, it opens until it is at the standby open-
ing position when the engine is started. This
operation takes approximately 3 seconds un-
til it is completed. Start the engine. If the er-
ror recurs, replace the throttle body assem-
bly.
Engine speed is high when the engine is idling.
7-20
FI ifl
Reinstatement
method
Reinstated by start- Reinstated by start- Reinstated by start-
ing the engine and ing the engine and ing the engine and
operating it at idle. operating it at idle. operating it at idle.
Reinstatement
method
Reinstated if the en- Reinstated if the en- Reinstated if the en- Reinstated if the en-
gine idle speed is gine idle speed is gine idle speed is gine idle speed is
within specification within specification within specification within specification
after starting the after starting the after starting the after starting the
engine. engine. engine. engine.