Yamaha YP400T Service Manual page 313

Fault code No. 50 Symptom
Used diagnostic code No. – –
Order Inspection operation item and
probable cause
1 Malfunction in ECU
Fault code No. 61 Symptom
Used diagnostic code No. – –
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 Open or short circuit in lead.
3 Detective ISC (idle speed control)
valve
Fault code No. Er-1 Symptom
Used diagnostic code No. – –
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 Open or short circuit in wiring har-
ness and/or sub lead.
3 Malfunction in meter
4 Malfunction in ECU
FUEL INJECTION SYSTEM
Faulty ECU memory. (When this malfunction is detected in the ECU, the fault
code number might not appear on the meter.)
Operation item and countermeasure
Replace the ECU.
ISC (idle speed control) valve open or short circuit is detected.
Operation item and countermeasure
If there is a malfunction, repair it and connect it
securely.
ISC (idle speed control) valve coupler
Main wiring harness ECU coupler
Sub-wire harness coupler
Repair or replace if there is an open or short circuit.
Between ISC (idle speed control) valve and ECU
coupler/main harness
pink – pink
light green – light green
gray – gray
sky blue – sky blue
Execute diagnostic mode (code No. 54)
Replace if defective.
Refer to "THROTTLE BODY AND FUEL INJEC-
TOR".
No signals are received from the ECU.
Operation item and countermeasure
If there is a malfunction, repair it and connect it
securely.
Main wiring harness ECU coupler
Sub-wire harness coupler
Repair or replace if there is an open or short circuit.
Between meter coupler and ECU coupler
yellow/blue – yellow/blue
Replace the meter.
Replace the ECU.
7 - 23
FI
Reinstatement
method
Reinstated by turn-
ing the main switch
ON.
Reinstatement
method
Reinstated by set-
ting the main
switch to ON. The
ISC (idle speed
control) valve fully
closes, and then it
opens until it is at
the standby open-
ing position when
the engine is
started.
Reinstatement
method
Reinstated if nor-
mal signal is
received from the
ECU when the
main switch is set
to ON.