Yamaha XV19SW Service Manual page 399

Fault code No. 37
Diagnostic code No.
Order Item/components and probable
cause
1 ECU fuse is blown.
2 Throttle valve does not fully close.
3 ISC valve is stuck fully open due to
disconnected ISC unit hose or cou-
pler. (High engine idle speed is de-
tected with the ISC valve stuck fully
open even though signals for the valve
to close are continuously being trans-
mitted by the ECU.)
4 ISC valve is not moving correctly.
Symptom Engine speed is high when the engine is idling.
54 ISC valve
Check or maintenance job
• Check the ECU fuse.
• Check the throttle bodies.
• Check the throttle cables.
• Check that the ISC unit hose is
• Check that the ISC unit coupler
• The ISC valve is stuck fully
• Execute the diagnostic mode.
• After the ISC valve is fully
7-55
FUEL INJECTION SYSTEM
Refer to "CHECKING THE
FUSES" on page 7-75.
Refer to "THROTTLE BODIES"
on page 6-6.
Refer to "ADJUSTING THE
THROTTLE CABLE FREE
PLAY" on page 3-8.
not disconnected.
is not disconnected.
open if it does not operate when
the main switch is turned "OFF".
(Touch the ISC unit with your
hand and check if it is vibrating
to confirm if the ISC valve is op-
erating.)
(Code No.54)
closed, it opens to the standby
opening position when the en-
gine is started. This operation
takes approximately 12 sec-
onds. Start the engine. If the er-
ror recurs, replace the throttle
body assembly.
Reinstatement
method
ISC valve re-
turns to its orig-
inal position by
turning the
main switch to
"ON" and back
to "OFF".
Reinstated if
the engine idle
speed is within
specification af-
ter starting the
engine.