Yamaha YW125Y_ Utility Trailer User Manual


 
6-20
FI
FUEL INJECTION SYSTEM
Open circuit detected in the primary lead of the ignition coil.
1
2
3
Fault codeNo.
33 Symptom
Used diagnostic code No. D30
Order
Inspection operation item and
probable cause
Operation item and countermeasure
Reinstatement
method
Reinstated by start-
ing the engine and
operating it at idle.
Connected condition of con-
nector
Inspect the coupler for any
pins that may have pulled
out.
Check the locking condition
of the coupler.
Open or short circuit in lead.
Defective ignition coil (test the
primary and secondary coils for
continuity).
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 7.
Engine speed is high when the engine is idling.
1
2
3
Fault code No.
37 Symptom
Used diagnostic code No. D54 (ISC (idle speed control) valve)
Order
Inspection operation item and
probable cause
Operation item and countermeasure
Reinstatement
method
Reinstated if the en-
gine idle speed is
within specification
after starting the
engine.
Throttle valve does not fully
close
ISC (idle speed control) valve
stuck fully open
ISC (idle speed control) valve
not moving correctly
Check the throttle body.
Refer to “THROTTLE BODY AND FUEL IN-
JECTOR” .
Check the throttle cable assembly.
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.)
TIP
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.
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