Yamaha XVS950CU 2014, Service Manual

Page: 453 / 580

FUEL INJECTION SYSTEM
7-62
6 Malfunction in ECU. Execute the diagnostic
mode. (Code No. 31)
No spark
→
Replace the
ECU.
Fault code No. 37
Item
A
Component other than ISC (idle speed control) unit is de-
fective (ISC operating sound is heard).
B
Defective ISC (idle speed control) unit (ISC operating sound is
not heard).
Fail-safe system
Able to start engine
Able to drive vehicle
Diagnostic code No. 54
Actuation
Fully closes the ISC valve, and then opens the valve. This opera-
tion is performed 3 times and takes approximately 4 seconds each
time. The “CHECK” indicator and “
” on the Yamaha diagnostic
tool screen comes on during the operation.
Procedure The ISC unit vibrates when the ISC valve operates.
Item
Probable cause of mal-
function and check
Maintenance job
Confirmation of service
completion
1 Locate the malfunction. Execute the diagnostic
mode. (Code No. 54)
Fully closes the ISC (idle
speed control) valve, and
then fully opens the valve. ISC operating sound is heard
→
Go to item 2.
ISC operating sound is not
heard
→
Go to item 2 in sec-
tion B for the defective ISC
(idle speed control) unit.
2 Incorrect speed sensor sig-
nal. Check the speed sensor.
Execute the diagnostic
mode. (Code No. 07)
Rotate the rear wheel by
hand and check that the indi-
cated value increases.
Value does not increase
→
Go to fault code No. 42.
Start the engine and let it idle
for approximately 10 sec-
onds.
Fault code number is not dis-
played
→
Service is finished.
Fault code number is dis-
played
→
Go to item 3.
3 Throttle valve does not fully
close. Check the throttle body as-
sembly.
Refer to “THROTTLE BOD-
IES” on page 6-6.
Check the throttle grip free
play.
Refer to “CHECKING THE
THROTTLE GRIP OPERA-
TION” on page 3-26. Start the engine and let it idle
for approximately 10 sec-
onds.
Fault code number is not dis-
played
→
Service is finished.
Fault code number is dis-
played
→
Go to item 4.
Fault code No. 34
Item
Rear cylinder ignition coil: open or short circuit detected in
the primary lead of the rear cylinder ignition coil.