Yamaha YP400T, YP400V, YP400W Service Manual page 294

Fault
Item
code No.
ISC (idle speed con-
37 trol) valve (stuck fully
open)
Fuel injector
39
Lean angle cut-off
30 switch (latch up
41 detected) (open or
short circuit)
Speed sensor
42
Fuel system voltage
43 (monitoring voltage)
Error in reading from or
writing on EEPROM
44
Vehicle system power
46 supply (monitoring volt-
age)
ECU internal malfunc-
tion (memory check
50
error)
ISC (idle speed con-
61 trol) valve unit (open or
short circuit)
Start unable warning
—
Communication error with the meter
Fault
Item
code No.
ECU internal malfunc-
Er-1 tion (output signal
error)
ECU internal malfunc-
Er-2 tion (output signal
error)
ECU internal malfunc-
Er-3 tion (output signal
error)
ECU internal malfunc-
Er-4
tion (input signal error)
FUEL INJECTION SYSTEM
Symptom
Engine speed is high when the
engine is idling.
Fuel injector open or short cir-
cuit is detected.
The scooter has overturned.
Lean angle cut-off switch-open
or short circuit is detected.
No normal signals are
received from the speed sen-
sor.
Supply power to the fuel injec-
tor and fuel pump is not nor-
mal.
An error is detected while
reading from or writing on
EEPROM (CO adjustment
value, code re-registering key
code, and throttle valve fully
closed notification value).
Power supply to the FI system
not normal
Faulty ECU memory. When
this malfunction is detected,
the code number might not
appear on the meter.
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. The
start switch is pushed when
fault code No.12, 19, 30, 33,
39, 41, or 50 is displayed to
indicate an error.
Symptom
No signals are received from
the ECU.
No signals are received from
the ECU within the specified
duration.
Data from the ECU cannot be
received correctly.
Non-registered data has been
received from the meter.
7 - 5
Fail-safe action
--
--
--
--
• Fixes the battery voltage
to 12 V.
--
--
--
--
Engine trouble warning light
flashes when the start
switch is turned ON.
Fail-safe action
–
–
–
–
FI
Engine start- Vehicle drive-
ability ability
Able Able
Unable Unable
Unable Unable
Able Able
Able Able
Able Able
Able Able
Unable Unable
Able Able
Unable Unable
Engine start- Vehicle drive-
ability ability
Unable Unable
Unable Unable
Unable Unable
Unable Unable