Fuel Injection System - Yamaha XF50W Service Manual

Fault
Item
code No.
39 Fuel injector
30 Lean angle cut-off switch
41 (latch up detected) (open or
short circuit)
42 Speed sensor
43 Fuel system voltage (moni-
toring voltage)
Error in reading from or writ-
44 ing on E2PROM
46 Vehicle system power sup-
ply (monitoring voltage)
ECU internal malfunction
50 (memory check error)
61 ISC (idle speed control) valve
unit (open or short circuit)
Start unable warning
_ Engine trouble warning light
flashes when the start
switch is turned ON.

FUEL INJECTION SYSTEM

Symptom
Fuel injector open or short circuit is de-
tected.
The vehicle has overturned.
Lean angle cut-off switch-open or short cir-
cuit is detected.
No normal signals are received from the
speed sensor.
Power supply to the fuel injector, fuel pump
and ignition coil are not normal.
An error is delected while reading from or
writing on E2PROM (CO adjustment
value).
Power supply to Fl system is not normal.
(red lead)
Faulty ECU memory. When this malfunc-
tion is detected, the code number might
not appear on the engine trouble warning
light or displayed on Fl diagnostic tool.
ISC (idle speed control) valve unit-open or
short circuit detected.
Relay is not activated even if the crank
signal is input while the start switch is
pushed.
7-6
Engine Vehicle
startability driveability
Unable Unable
Unable Unable
Able Able
Able Able
Able Able
Able Able
Unable Unable
Able Able
Unable Unable