sensor YAMAHA WR 250F 2015 Owner's Guide

ELECTRICAL COMPONENTS....................................................................... 9-60
CHECKING THE SWITCHES .................................................................. 9-64
CHECKING THE BULBS AND BULB SOCKETS .................................... 9-67
CHECKING THE FUSES ......................................................................... 9-68
CHECKING AND CHARGING THE BATTERY ........................................ 9-69
CHECKING THE RELAYS ....................................................................... 9-72
CHECKING THE DIODE .......................................................................... 9-73
CHECKING THE IGNITION SPARK GAP................................................ 9-73
CHECKING THE SPARK PLUG CAP ...................................................... 9-73
CHECKING THE IGNITION COIL ............................................................ 9-74
CHECKING THE CRANKSHAFT POSITION SENSOR........................... 9-74
CHECKING THE LEAN ANGLE SENSOR............................................... 9-75
CHECKING THE STARTER MOTOR OPERATION ................................ 9-75
CHECKING THE STATOR COIL ............................................................. 9-76
CHECKING THE RECTIFIER/REGULATOR ........................................... 9-76
CHECKING THE SPEED SENSOR ......................................................... 9-77
CHECKING THE FUEL SENDER ............................................................ 9-77
CHECKING THE RESISTER ................................................................... 9-77
CHECKING THE RADIATOR FAN MOTOR ............................................ 9-78
CHECKING THE COOLANT TEMPERATURE SENSOR........................ 9-78
CHECKING THE THROTTLE POSITION SENSOR ................................ 9-79
CHECKING THE THROTTLE POSITION SENSOR INPUT VOLTAGE .. 9-79
CHECKING THE INTAKE AIR PRESSURE SENSOR ............................ 9-80
CHECKING THE INTAKE AIR TEMPERATURE SENSOR ..................... 9-80
CHECKING THE FUEL INJECTOR ......................................................... 9-81

IGNITION SYSTEM
9-3
1. Joint connector
2. Joint connector
4. AC magneto
9. Battery
10.Frame ground
11.Starter relay
12.Main fuse
22.ECU (engine control unit)
23.Ignition coil
24.Spark plug
30.Joint connector
35.Lean angle sensor
36.Engine stop switch
48.Frame ground

IGNITION SYSTEM
9-4
EAS2GB2361TROUBLESHOOTING
The ignition system fails to operate (no spark or intermittent spark).
TIP
Before troubleshooting, remove the following part (s):
1. Seat
2. Side cover (left/right)
3. Air scoop (left/right)
4. Fuel tank
5. Fuel tank
1. Check the fuse.
Refer to “CHECKING THE FUSES”
on page 9-68.NG 
Replace the fuse(s).
OK 
2. Check the battery.
Refer to “CHECKING AND
CHARGING THE BATTERY” on
page 9-69.NG 
• Clean the battery terminals.
• Recharge or replace the battery.
OK 
3. Check the spark plug.
Refer to “CHECKING THE FUSES”
on page 9-68.NG 
Re-gap or replace the spark plug.
OK 
4. Check the ignition spark gap.
Refer to “CHECKING THE IGNI-
TION SPARK GAP” on page 9-73.OK 
The ignition system is normal.
NG 
5. Check the ignition coil.
Refer to “CHECKING THE IGNI-
TION COIL” on page 9-74.NG 
Replace the ignition coil.
OK 
6. Check the crankshaft position sen-
sor.
Refer to “CHECKING THE CRANK-
SHAFT POSITION SENSOR” on
page 9-74.NG 
Replace the stator assembly.
OK 
7. Check the engine stop switch.
Refer to “CHECKING THE
SWITCHES” on page 9-64.NG 
Replace the engine stop switch.
OK 

IGNITION SYSTEM
9-5
8. Check the lean angle sensor.
Refer to “CHECKING THE LEAN
ANGLE SENSOR” on page 9-75.NG 
Replace the lean angle sensor.
OK 
9. Check the entire ignition system’s
wiring.
Refer to “CIRCUIT DIAGRAM” on
page 9-2.NG 
Properly connect or repair the ignition sys-
tem’s wiring.
OK 
Replace the ECU.

SIGNALING SYSTEM
9-21
1. Joint connector
2. Joint connector
3. Joint connector
7. Main relay
9. Battery
10.Frame ground
11.Starter relay
12.Main fuse
15.Indicator light
17.Fuel level warning light
18.Resistor
19.Fuel sender
22.ECU (engine control unit)
30.Joint connector
42.Joint connector
46.Speed sensor
47.Multi-function display
48.Frame ground

SIGNALING SYSTEM
9-22
EAS2GB2370TROUBLESHOOTING
• The speedometer does not operate normally.
• The fuel indicator light does not come on.
TIP
Before troubleshooting, remove the following part (s):
1. Seat
2. Side cover (left/right)
3. Air scoop (left/right)
4. Fuel tank
Check the signaling system
The speedometer fails to operate.
1. Check the fuse.
Refer to “CHECKING THE FUSES”
on page 9-68.NG 
Replace the fuse(s).
OK 
2. Check the battery.
Refer to “CHECKING AND
CHARGING THE BATTERY” on
page 9-69.NG 
• Clean the battery terminals.
• Recharge or replace the battery.
OK 
3. Check the main relay.
Refer to “CHECKING THE RE-
LAYS” on page 9-72.NG 
Replace the main relay.
OK 
4. Check the entire signaling system’s
wiring.
Refer to “CIRCUIT DIAGRAM” on
page 9-20.NG 
Properly connect or repair the signaling
system’s wiring.
OK 
This circuit is OK.
1. Check the speed sensor.
Refer to “CHECKING THE SPEED
SENSOR” on page 9-77.NG 
Replace the speed sensor.
OK 
2. Check the entire signaling system’s
wiring.
Refer to “CIRCUIT DIAGRAM” on
page 9-20.NG 
Properly connect or repair the signaling
system’s wiring.
OK 
Replace the meter assembly.

COOLING SYSTEM
9-25
1. Joint connector
2. Joint connector
3. Joint connector
7. Main relay
9. Battery
10.Frame ground
11.Starter relay
12.Main fuse
22.ECU (engine control unit)
27.Radiator fan motor relay
28.Radiator fan motor fuse
29.Radiator fan motor
30.Joint connector
32.Coolant temperature sensor
48.Frame ground

COOLING SYSTEM
9-26
EAS2GB2373TROUBLESHOOTING
The radiator fan motor fails to turn.
TIP
Before troubleshooting, remove the following part(s):
1. Seat
2. Side cover (left)
3. Air scoop (left/right)
4. Fuel tank
1. Check the fuse.
Refer to “CHECKING THE FUSES”
on page 9-68.NG 
Replace the fuse(s).
OK 
2. Check the battery.
Refer to “CHECKING AND
CHARGING THE BATTERY” on
page 9-69.NG 
• Clean the battery terminals.
• Recharge or replace the battery.
OK 
3. Check the main relay.
Refer to “CHECKING THE RE-
LAYS” on page 9-72.NG 
Replace the main relay.
OK 
4. Check the radiator fan motor.
Refer to “CHECKING THE RADIA-
TOR FAN MOTOR” on page 9-78.NG 
Replace the radiator fan motor.
OK 
5. Check the radiator fan motor relay.
Refer to “CHECKING THE RE-
LAYS” on page 9-72.NG 
Replace the radiator fan motor relay.
OK 
6. Check the coolant temperature sen-
sor.
Refer to “CHECKING THE COOL-
ANT TEMPERATURE SENSOR”
on page 9-78.NG 
Replace the coolant temperature sensor.
OK 
7. Check the entire cooling system’s
wiring.
Refer to “CIRCUIT DIAGRAM” on
page 9-16.NG 
Properly connect or repair the cooling sys-
tem’s wiring.
OK 
Replace the ECU.

FUEL INJECTION SYSTEM
9-29
1. Joint connector
2. Joint connector
3. Joint connector
4. AC magneto
7. Main relay
9. Battery
10.Frame ground
11.Starter relay
12.Main fuse
15.Indicator light
16.Engine trouble warning light
22.ECU (engine control unit)
25.Injector
30.Joint connector
31.Intake air temperature sensor
32.Coolant temperature sensor
33.Throttle position sensor
34.Intake air pressure sensor
35.Lean angle sensor
36.Engine stop switch
37.Neutral switch
38.Diode
39.Starting circuit cut-off relay
40.Clutch switch
42.Joint connector
48.Frame ground

FUEL INJECTION SYSTEM
9-30
EAS2GB2376ECU SELF-DIAGNOSTIC FUNCTION
The ECU is equipped with a self-diagnostic function in order to ensure that the fuel injection system
is operating normally. If this function detects a malfunction in the system, it immediately operates the
engine under substitute characteristics and illuminates the engine trouble warning light to alert the
rider that a malfunction has occurred in the system. Once a malfunction has been detected, a fault
code number is stored in the memory of the ECU.
• To inform the rider that the fuel injection system is not functioning, the engine trouble warning light
flashes while the start switch is being pushed to start the engine.
• If a malfunction is detected in the system by the self-diagnostic function, the ECU provides an ap-
propriate substitute characteristic operation, and alerts the rider of the detected malfunction by illu-
minating the engine trouble warning light.
Engine trouble warning light indication and fuel injection system operation
* The warning light flashes when any one of the following conditions is present and the start switch
is pushed:
Checking the engine trouble warning light
The engine trouble warning light comes on for around 2 seconds when pushing the start switch to
turn on the meter light and the engine trouble warning light comes on while the start switch is being
pushed.Warning light indica-
tionECU operationFuel injection opera-
tionVehicle operation
Flashing* Warning provided
when unable to start
engineOperation stopped Cannot be operated
Remains on Malfunction detected Operated with substi-
tute characteristics in
accordance with the
description of the mal-
functionCan or cannot be oper-
ated depending on the
fault code
12: Crankshaft position sensor 41: Lean angle sensor
(open or short circuit)
30: Lean angle sensor
(latch up detected)50: ECU internal malfunction
(faulty ECU memory)
33: Ignition coil
(Malfunction detected in the primary wire
of the ignition coil)
a. The meter light does not come on.
b. The meter light comes on.
c. Light OFF
d. Light ON for 2 seconds
ab
c cd