2017 YAMAHA WR 250F fuel

9
ELECTRICAL SYSTEM
IGNITION SYSTEM.......................................................................................... 9-2
CIRCUIT DIAGRAM ................................................................................... 9-2
TROUBLESHOOTING ............................................................................... 9-4
ELECTRIC STARTING SYSTEM..................................................................... 9-6
CIRCUIT DIAGRAM ................................................................................... 9-6
STARTING CIRCUIT CUT-OFF SYSTEM OPERATION ........................... 9-8
TROUBLESHOOTING ............................................................................. 9-10
CHARGING SYSTEM..................................................................................... 9-12
CIRCUIT DIAGRAM ................................................................................. 9-12
TROUBLESHOOTING ............................................................................. 9-14
LIGHTING SYSTEM....................................................................................... 9-16
CIRCUIT DIAGRAM ................................................................................. 9-16
TROUBLESHOOTING ............................................................................. 9-18
SIGNALING SYSTEM.................................................................................... 9-20
CIRCUIT DIAGRAM ................................................................................. 9-20
TROUBLESHOOTING ............................................................................. 9-22
COOLING SYSTEM........................................................................................ 9-24
CIRCUIT DIAGRAM ................................................................................. 9-24
TROUBLESHOOTING ............................................................................. 9-26
FUEL INJECTION SYSTEM........................................................................... 9-28
CIRCUIT DIAGRAM ................................................................................. 9-28
ECU SELF-DIAGNOSTIC FUNCTION ..................................................... 9-30
TROUBLESHOOTING METHOD ............................................................. 9-31
YAMAHA DIAGNOSTIC TOOL ................................................................ 9-32
TROUBLESHOOTING DETAILS ............................................................. 9-35
FUEL PUMP SYSTEM.................................................................................... 9-56
CIRCUIT DIAGRAM ................................................................................. 9-56
TROUBLESHOOTING ............................................................................. 9-58

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 ...................................................... 9-74
CHECKING THE IGNITION COIL ............................................................ 9-74
CHECKING THE CRANKSHAFT POSITION SENSOR........................... 9-75
CHECKING THE LEAN ANGLE SENSOR............................................... 9-75
CHECKING THE STARTER MOTOR OPERATION ................................ 9-76
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 ................................................................... 9-78
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 .. 9-80
CHECKING THE INTAKE AIR PRESSURE SENSOR ............................ 9-80
CHECKING THE INTAKE AIR TEMPERATURE SENSOR ..................... 9-80
CHECKING THE FUEL INJECTOR ......................................................... 9-81

IGNITION SYSTEM
9-4
EAS2GBB359TROUBLESHOOTING
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. Air filter case cover
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 SPARK
PLUG” on page 3-40.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 9-75.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 

ELECTRIC STARTING SYSTEM
9-10
EAS2GBB362TROUBLESHOOTING
The starter motor fails to turn.
TIP
Before troubleshooting, remove the following part (s):
1. Seat
2. Side cover (left/right)
3. Air scoop (left/right)
4. Fuel tank
5. Air filter case cover
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 starter motor operation.
Refer to “CHECKING THE START-
ER MOTOR OPERATION” on page
9-76.OK 
Starter motor is OK. Perform the electric
starting system troubleshooting, starting
with step 5.
NG 
4. Check the starter motor.
Refer to “CHECKING THE START-
ER MOTOR” on page 6-39.NG 
Repair or replace the starter motor.
OK 
5. Check the relay unit (Starting circuit
cut-off relay).
Refer to “CHECKING THE RE-
LAYS” on page 9-72.NG 
Replace the relay unit.
OK 
6. Check the diode.
Refer to “CHECKING THE DIODE”
on page 9-73.NG 
Replace the diode.
OK 
7. Check the starter relay.
Refer to “CHECKING THE RE-
LAYS” on page 9-72.NG 
Replace the starter relay.
OK 

LIGHTING SYSTEM
9-18
EAS2GBB366TROUBLESHOOTING
Any of the following fail to light: headlight or meter light.
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 each bulbs condition.
Refer to “CHECKING THE BULBS
AND BULB SOCKETS” on page 9-
67.NG 
Replace the bulb (s).
OK 
2. Check the fuse.
Refer to “CHECKING THE FUSES”
on page 9-68.NG 
Replace the fuse(s).
OK 
3. 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 
4. Check the main relay.
Refer to “CHECKING THE RE-
LAYS” on page 9-72.NG 
Replace the main relay.
OK 
5. Check the headlight relay.
Refer to “CHECKING THE RE-
LAYS” on page 9-72.NG 
Replace the headlight relay.
OK 
6. Check the entire lighting system’s
wiring.
Refer to “CIRCUIT DIAGRAM” on
page 9-16.NG 
Properly connect or repair the lighting sys-
tem’s wiring.
OK 
Replace the ECU, meter assembly, or
taillight.

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
EAS2GBB368TROUBLESHOOTING
• 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.

SIGNALING SYSTEM
9-23
The fuel level warning light fails to come on.
1. Check the fuel sender.
Refer to “CHECKING THE FUEL
SENDER” on page 9-77.NG 
Replace the fuel sender assembly.
OK 
2. Check the resistor.
Refer to “CHECKING THE RESIST-
ER” on page 9-78.NG 
Replace the resistor.
OK 
3. 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 indicator light assembly.