Yamaha WR125R 2009, Service Manual

Page: 339 / 372

FUEL INJECTION SYSTEM
8-54
Fault code No. 46 Symptom Power supply to the fuel injection system is not normal.
Diagnostic code No. — —
Order Item/components and probable
cause
Check or maintenance job Reinstatement
method
1 Connections
• Wire harness ECU coupler • Check the coupler for any pins
that may have pulled out.
• Check the locking condition of
the coupler.
• If there is a malfunction, repair it
and connect the coupler se-
curely.
Start the en-
gine and let it
run at idle.
2 Faulty battery. • Replace or charge the battery.
Refer to “CHECKING AND
CHARGING THE BATTERY” on
page 8-65.
3 Malfunction in rectifier/regulator • Replace if defective.
Refer to “CHECKING THE
RECTIFIER/REGULATOR” on
page 8-72.
4 Open or short circuit in wire harness. • Repair or replace if there is an
open or short circuit.
• Between battery and main fuse
terminal.
(red–red)
• Between main fuse terminal
and main switch coupler.
(red–red)
• Between main switch coupler
and fuse box terminal (ignition
fuse).
(brown/blue–brown/blue)
• Between fuse box terminal (ig-
nition fuse) and ECU coupler.
(red/black–red/black)
Fault code No. 50 Symptom Faulty ECU memory. (When this malfunction is detected in
the ECU, the fault code number might not appear on the FI
diagnostic tool.)
Diagnostic code No. — —
Order Item/components and probable
cause
Check or maintenance job Reinstatement
method
1 Malfunction in ECU. • Replace the ECU.
TIP
Do not replace the ECU with the
main switch set to “ON”.
Set the main
switch to “ON”.