Yamaha WR450F 2021 Owner's Service Manual page 317

The fuel level warning light fails to come on.
1. Check the fuel sender.
Refer to "CHECKING THE FUEL
SENDER" on page 8-68.
OK
2. Check the resistor.
Refer to "CHECKING THE RESIS-
TOR" on page 8-68.
OK
3. Check the entire signaling system's
wiring.
Refer to "CIRCUIT DIAGRAM" on
page 8-15.
OK
Replace the ECU.
SIGNALING SYSTEM
Replace the fuel pump assembly.
NG
Replace the resistor.
NG
Properly connect or repair the signaling
system's wiring.
NG
8-18