Yamaha MBK MW125 2014, Service Manual

Page: 338 / 380

FUEL INJECTION SYSTEM
8-41
Fault code No. 37
Diagnostic code No. 08
Tool display
Lean angle sensor output voltage
• 0.4–1.4 (upright)
• 3.7–4.4 (overturned)
Procedure Remove the lean angle sensor and incline it more than 50 degrees.
Item
Probable cause of malfunc-
tion and check
Maintenance job
Confirmation of service com-
pletion
1 The vehicle has overturned. Raise the vehicle upright. Turn the main switch to “ON”,
then to “OFF”, and then back to
“ON”.
Fault code number is not dis-
played
→
Service is finished.
Fault code number is displayed
→
Go to item 2.
2 Installed condition of lean an-
gle sensor. Check the installed direction
and condition of the sensor. Turn the main switch to “ON”,
then to “OFF”, and then back to
“ON”.
Fault code number is not dis-
played
→
Service is finished.
Fault code number is displayed
→
Go to item 3.
3 Defective lean angle sensor. Execute the diagnostic mode.
(Code No. 08)
Replace if defective.
Refer to “CHECKING THE
LEAN ANGLE SENSOR” on
page 8-65. Turn the main switch to “ON”,
then to “OFF”, and then back to
“ON”.
Fault code number is not dis-
played
→
Service is finished.
Fault code number is displayed
→
Go to item 4.
4 Malfunction in ECU. Replace the ECU.
Refer to “REPLACING THE
ECU (engine control unit)” on
page 8-59.
Fault code No. 30
Item Latch up detected.
Fault code No. 37
Item Engine speed is high when the engine is idling.
Fail-safe system
Able to start engine
Able to drive vehicle
Diagnostic code No. 54
Action
The ISC (idle speed control) valve fully closes, and then it turn back fully
opens.
This operation takes approximately 3 seconds.
Procedure Check that ISC valve is actuated by listening for the operating sound.
Item
Probable cause of malfunc-
tion and check
Maintenance job
Confirmation of service com-
pletion
1 Locate the malfunction. Execute the diagnostic mode.
(Code No. 54)
Check that ISC valve is actuat-
ed by listening for the operating
sound. ISC valve operation sound is
heard.
→
Go to item A-1.
ISC valve operation sound is
not heard.
→
Go to item B-1.