2016 YAMAHA WR 450F ECU

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.

ELECTRIC STARTING SYSTEM
9-7
1. Joint connector
2. Joint connector
3. Joint connector
7. Main relay
9. Battery
10.Frame ground
11.Starter relay
12.Main fuse
13.Starter motor
14.Starter relay diode
22.ECU (engine control unit)
30.Joint connector
36.Engine stop switch
37.Neutral switch
38.Diode
39.Starting circuit cut-off relay
40.Clutch switch
41.Start switch
48.Frame ground
50.Negative battery lead

ELECTRIC STARTING SYSTEM
9-11
8. Check the main relay.Refer to “CHECKING THE RE-
LAYS” on page 9-72. NG

Replace the main relay.
OK 
9. Check the neutral switch. Refer to “CHECKING THE
SWITCHES” on page 9-64. NG

Replace the neutral switch.
OK 
10.Check the clutch switch. Refer to “CHECKING THE
SWITCHES” on page 9-64. NG

Replace the clutch switch.
OK 
11.Check the engine stop switch. Refer to “CHECKING THE
SWITCHES” on page 9-64. NG

Replace the engine stop switch.
OK 
12.Check the start switch. Refer to “CHECKING THE
SWITCHES” on page 9-64. NG

Replace the start switch.
OK 
13.Check the entire starting system’s wiring.
Refer to “CIRCUIT DIAGRAM” on
page 9-6. NG

Properly connect or repair the starting sys-
tem’s wiring.
OK 
Replace the ECU.

LIGHTING SYSTEM
9-17
1. Joint connector
2. Joint connector
6. Headlight relay
7. Main relay
9. Battery
10.Frame ground
11.Starter relay
12.Main fuse
22.ECU (engine control unit)
30.Joint connector
42.Joint connector
43.Taillight
44.Headlight
47.Multi-function display
48.Frame ground
50.Negative battery lead

LIGHTING SYSTEM
9-18
EAS2GC1367TROUBLESHOOTING
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 tank1. 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
50.Negative battery lead

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
50.Negative battery lead

COOLING SYSTEM
9-26
EAS2GC1372TROUBLESHOOTING
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 tank1. 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.