2016 YAMAHA WR 450F engine

FUEL INJECTION SYSTEM
9-50
TIP
Before troubleshooting, disconnect the starter motor lead from the starter relay.
Fault code No. 44
Item EEPROM fault code number: an error is detected while read-
ing or writing on EEPROM.
Fail-safe system Able/Unable to start engine
Able/Unable to drive vehicle
Diagnostic code No. 60
Diagnostic tool display EEPROM fault code display
• 00: No fault
• 01: CO adjustment value
• 07: Setting tool adjustment values 0–8 for fuel injection amount or
ignition timing
Procedure —
Item Probable cause of malfunc-
tion and check Maintenance jobConfirmation of service
completion
1 Locate the malfunction Ex ecute the diagnostic mode
(Code No. 60).
00: Go to item 4.
01: Go to item 2.
07: Go to item 3. —
2 “01” is indicated in Diagnostic mode (Code No. 60) EEP-
ROM data error for adjust-
ment of CO concentration Change the CO concentra-
tion, and rewrite in EEPROM.
After this adjustment, push
the engine stop switch, then
push the start switch.
Memory not recovered
 Re-
place the ECU. Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Repeat the proce-
dure in item 1. If the same
number is indicated, perform
the procedure in item 4.
3 “07” is indicated in Diagnostic mode (Code No. 60) EEP-
ROM data error for setting
tool adjustment values for
fuel injection amount or igni-
tion timing. Erase the setting map in the
diagnostic mode (diagnostic
code No. 65).
Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Repeat the proce-
dure in item 1. If the same
number is indicated, perform
the procedure in item 4.
4 Malfunction in ECU. Replace the ECU.

FUEL INJECTION SYSTEM
9-51
Fault code No.46
Item Charging voltage is abnormal.
Fail-safe system Able/Unable to start engine
Able/Unable to drive vehicle
Diagnostic code No. —
Diagnostic tool display —
Procedure —
Item Probable cause of malfunc-
tion and check Maintenance jobConfirmation of service
completion
1 Connection of wire harness ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins). Improperly connected

Connect the coupler securely
or repair/replace the wire har-
ness. Start the engine and let it idle
for approximately 5 seconds.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 2.
2 Wire harness continuity. Open or short circuit Re-
place the wire harness.
Between rectifier/regulator
coupler and ECU coupler.
red–red
Between battery terminal and
ECU coupler.
red–red Start the engine and let it idle
for approximately 5 seconds.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 3.
3 Defective AC magneto. Check the AC magneto. Refer to “CHARGING SYS-
TEM” on page 9-12.
Defective AC magneto  Re-
place. Start the engine and let it idle
for approximately 5 seconds.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 4.
4 Malfunction in ECU. Replace the ECU.

FUEL INJECTION SYSTEM
9-52
TIP
Before troubleshooting, disconnect the starter motor lead from the starter relay.
TIP
Before troubleshooting, disconnect the starter motor lead from the starter relay.
Fault code No. 50
Item
Faulty ECU memory. (When this malfunction is detected in the
ECU, the fault code number might not appear on the meter.)
Fail-safe system Unable to start engine
Unable to drive vehicle
Diagnostic code No. —
Diagnostic tool display —
Procedure —
Item Probable cause of malfunc-
tion and check Maintenance jobConfirmation of service
completion
1 Malfunction in ECU. Replace the ECU. Push the start switch. Check that the fault code
number is not displayed.
Fault code No. waiting for connection
Item No communication signal is received from the ECU.
Fail-safe system Able to start engine (Unable when ECU is malfunctioning)
Able to drive vehicle (Unable when ECU is malfunctioning)
Diagnostic code No. —
Diagnostic tool display —
Procedure —
Item Probable cause of malfunc-
tion and check Maintenance jobConfirmation of service
completion
1 Connection of Yamaha diag- nostic tool coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins). Improperly connected

Connect the coupler securely
or repair/replace the wire har-
ness. Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 2.
2 Connection of wire harness ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins). Improperly connected

Connect the coupler securely
or repair/replace the wire har-
ness. Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 3.

FUEL INJECTION SYSTEM
9-53
TIP
Before troubleshooting, disconnect the starter motor lead from the starter motor.3 Wire harness continuity. Open or short circuit
 Re-
place the wire harness.
light green–light green Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 4.
4 Yamaha diagnostic tool mal- function. Replace the Yamaha diag-
nostic tool. Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 5.
5 Malfunction in ECU. Replace the ECU.
Fault code No. Er-2
Item Signals from the ECU cannot be received within the specified
period of time.
Fail-safe system Able to start engine
Able to drive vehicle
Diagnostic code No. —
Diagnostic tool display —
Procedure —
Item Probable cause of malfunc-
tion and check Maintenance jobConfirmation of service
completion
1 Connection of Yamaha diag- nostic tool coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins). Improperly connected

Connect the coupler securely
or repair/replace the wire har-
ness. Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 2.
2 Connection of wire harness ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins). Improperly connected

Connect the coupler securely
or repair/replace the wire har-
ness. Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 3.
3 Wire harness continuity. Open or short circuit  Re-
place the wire harness.
light green–light green Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 4.
Fault code No.
waiting for connection
Item No communication signal is received from the ECU.

FUEL INJECTION SYSTEM
9-54
TIP
Before troubleshooting, disconnect the starter motor lead from the starter motor.4 Yamaha diagnostic tool mal-
function. Replace the Yamaha diag-
nostic tool. Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 5.
5 Malfunction in ECU. Replace the ECU.
Fault code No. Er-3
Item Data from the ECU cannot be received correctly.
Fail-safe system Able to start engine
Able to drive vehicle
Diagnostic code No. —
Diagnostic tool display —
Procedure —
Item Probable cause of malfunc-
tion and check Maintenance jobConfirmation of service
completion
1 Connection of Yamaha diag- nostic tool coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins). Improperly connected

Connect the coupler securely
or repair/replace the wire har-
ness. Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 2.
2 Connection of wire harness ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins). Improperly connected

Connect the coupler securely
or repair/replace the wire har-
ness. Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 3.
3 Wire harness continuity. Open or short circuit  Re-
place the wire harness.
light green–light green Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 4.
4 Yamaha diagnostic tool mal- function. Replace the Yamaha diag-
nostic tool. Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 5.
5 Malfunction in ECU. Replace the ECU. Fault code No. Er-2
Item Signals from the ECU cannot be received within the specified
period of time.

FUEL INJECTION SYSTEM
9-55
TIP
Before troubleshooting, disconnect the starter motor lead from the starter relay.
Fault code No. Er-4
Item Registered data cannot be received from the Yamaha diagnos-
tic tool.
Fail-safe system Able to start engine
Able to drive vehicle
Diagnostic code No. —
Diagnostic tool display —
Procedure —
Item Probable cause of malfunc-
tion and check Maintenance jobConfirmation of service
completion
1 Connection of Yamaha diag- nostic tool coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins). Improperly connected

Connect the coupler securely
or repair/replace the wire har-
ness. Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 2.
2 Connection of wire harness ECU coupler.
Check the locking condition
of the coupler.
Disconnect the coupler and
check the pins (bent or bro-
ken terminals and locking
condition of the pins). Improperly connected

Connect the coupler securely
or repair/replace the wire har-
ness. Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 3.
3 Wire harness continuity. Open or short circuit  Re-
place the wire harness.
light green–light green Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 4.
4 Yamaha diagnostic tool mal- function. Replace the Yamaha diag-
nostic tool. Push the start switch.
Fault code number is not dis-
played
 Service is finished.
Fault code number is dis-
played  Go to item 5.
5 Malfunction in ECU. Replace the ECU.

FUEL PUMP SYSTEM
9-57
1. Joint connector
2. Joint connector
9. Battery
10.Frame ground
11.Starter relay
12.Main fuse
22.ECU (engine control unit)
26.Fuel pump
30.Joint connector
36.Engine stop switch
48.Frame ground
50.Negative battery lead

FUEL PUMP SYSTEM
9-58
EAS2GC1381TROUBLESHOOTING
The fuel pump fails to operate.
TIP
Before troubleshooting, remove the following part(s):
1. Seat
2. Side cover (left/right)
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 engine stop switch. Refer to “CHECKING THE
SWITCHES” on page 9-64. NG

Replace the engine stop switch.
OK 
4. Check fuel pressure. Refer to “CHECKING THE FUEL
PRESSURE” on page 8-5. NG

Replace the fuel pump.
OK 
5. Check the fuel pump system wire harness connections.
Refer to “CIRCUIT DIAGRAM” on
page 9-56. NG

Properly connect or repair the fuel pump
system’s wiring.
OK 
Replace the ECU.