Yamaha YP400T Service Manual page 311

Fault code No. 43 Symptom
Used diagnostic code No. 09 (fuel system voltage)
Order Inspection operation item and
probable cause
1 Connected condition of connector
Inspect the coupler for any pins
that may have pulled out.
Check the locking condition of the
coupler.
2 Malfunction in ECU
3 Open or short circuit in the wiring
harness.
4 Malfunction or open circuit in fuel
injection system relay
FUEL INJECTION SYSTEM
Supply power to the fuel injector and fuel pump is not normal.
Operation item and countermeasure
If there is a malfunction, repair it and connect it
securely.
Fuel injection system relay coupler
Fuel pump coupler
Fuel injector coupler
ECU coupler
Fuel injection system relay is on.
Repair or replace if there is an open or short circuit.
Between battery and ECU coupler
red – red
red/blue – red/blue
Execute the diagnostic mode (code No. 09)
NOTE:
When the leads are disconnected, the voltage check
by the code No. 09 is impossible.
Replace if defective.
1. Remove the fuel injection system relay.
2. Connect the pocket tester (Ω × 1) and battery
(12 V) to the starting circuit cut-off relay terminals
as shown.
Positive battery terminal → red/black 1
Negative battery terminal → red/yellow 2
Positive tester probe → red 3
Negative tester probe → red/blue 4
3
4
2
3. Does the fuel injection system relay have conti-
nuity between red and red/blue?
7 - 21
1
R/Y R/B
R/L
R
FI
Reinstatement
method
Reinstated by
starting the engine
and operating it at
idle.