Troubleshooting - Yamaha YZ450FF 1SL-28199-11 Owner's Service Manual

TROUBLESHOOTING

EAS1SL5333
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 tank
5. Air filter case cover
1. Check the fuel pump system wire
harness connections.
OK 
2. Check the engine stop switch.
Refer to "CHECKING THE
SWITCHES" on page 8-38.
OK 
3. Check fuel pressure.
Refer to "CHECKING THE FUEL
PRESSURE" on page 7-3.
OK 
4. Check the fuel pump system wire
harness.
Refer to "CIRCUIT DIAGRAM" on
page 8-32.
OK 
Replace the ECU.
FUEL PUMP SYSTEM
NG 
Reconnect.
NG 
Replace the engine stop switch.
NG 
Replace the fuel pump.
NG 
Repair or replace the wire harness.
8-34