Yamaha 2010 XMAX YP125R Service Manual page 442

Fault code No.
Item
Fail-safe system
Diagnostic code No.
Actuation
Checking method
Probable cause of malfunction
1 Throttle valve does not fully close.
2 ISC valve is stuck fully open due to dis-
connected ISC unit coupler. (High engine
idle speed is detected with the ISC valve
stuck fully open even though signals for
the valve to close are continuously being
transmitted by the ECU.)
3 ISC valve is not moving correctly.
Reinstatement method
Fault code No.
Item
Fail-safe system
Diagnostic code No.
Actuation
Checking method
37
ISC valve: engine speed is high when the engine is idling.
Able to start engine
Able to drive vehicle
54
Actuates and fully closes the ISC valve, then opens it to the stand-
by opening position when the engine is started.
This operation takes approximately 12 seconds until it is complet-
ed.
The ISC unit vibrates when the ISC valve operates.
• Check the throttle body.
Refer to "THROTTLE BODY" on page 7-5.
• Check the throttle cables.
Refer to "ADJUSTING THE THROTTLE CA-
BLE FREE PLAY" on page 3-9 and "ADJUST-
ING THE THROTTLE CABLE FREE PLAY" on
page 3-23.
• Check that the ISC unit coupler is not discon-
nected.
• The ISC valve is stuck fully 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.)
• Execute the diagnostic mode. (Code No. 54)
• After the ISC valve is fully closed, it opens to
the standby opening position when the engine
is started. This operation takes approximately
12 seconds. Start the engine. If the error re-
curs, replace the throttle body assembly.
ISC valve returns to its original position by turning the main switch
to "ON" and back to "OFF".
Reinstated if the engine idle speed is within specification after
starting the engine.
39
Injector: open or short circuit detected.
Unable to start engine
Unable to drive vehicle
36
Actuates the injector five times at one-second intervals.
Illuminates the "WARNING" LED on the FI diagnostic tool and the
engine trouble warning light.
Check that the injector actuates five times by listening to the oper-
ating sound.
8-45
FUEL INJECTION SYSTEM
Check or maintenance job