Yamaha YP125R, Service Manual

Page: 431 / 498

FUEL INJECTION SYSTEM
8-34
When an abnormal signal is received from a sensor, the ECU processes the specified values that are
programmed for each sensor in order to provide the engine with alternate operating instructions that
enable the engine to continue operating or stop operating, depending on the conditions.
EAS27400
TROUBLESHOOTING METHOD
The engine operation is not normal and the
engine trouble warning light comes on.
1. Check:
• Fault code number
▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼ ▼▼▼ ▼ ▼▼▼
a. Check the fault code number displayed on
the meter.
b. Identify the faulty system with the fault code
number.
c. Identify the probable cause of the malfunc-
tion.
▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲ ▲▲▲ ▲ ▲▲▲
2. Check and repair the probable cause of the
malfunction.
3. Perform the reinstatement action for the fuel
injection system.
Refer to “Reinstatement method” in the ap-
propriate table in “TROUBLESHOOTING
DETAILS” on page 8-36.
4. Set the main switch to “OFF”, then to “ON”
again, and then check that no fault code num-
ber is displayed.
TIP
If another fault code number is displayed, repeat
steps (1) to (4) until no fault code number is dis-
played.
5. Erase the malfunction history in the diagnos-
tic mode. Refer to “DIAGNOSTIC CODE TA-
BLE” on page 8-54 (Diagnostic code No. 62).
TIP
Setting the main switch to “OFF” will not erase
the malfunction history.
The engine operation is not normal, but the
engine trouble warning light does not come
on.
1. Check the operation of the following sensors
and actuators in the Diagnostic mode. Refer
to “TROUBLESHOOTING DETAILS” on
page 8-36.
If a malfunction is detected in the sensors or
actuators, repair or replace all faulty parts.
If no malfunction is detected in the sensors
and actuators, check and repair the inner
parts of the engine.
EAS27441
DIAGNOSTIC MODE
It is only possible to monitor the sensor output data or check the activation of actuators by connecting
the FI diagnostic tool to the vehicle and setting the diagnostic mode.
TIP
The diagnostic mode can only be set using the FI diagnostic tool. The diagnostic mode cannot be set
using the meter.
Fault code No. No fault code No.
Check and repair.
Refer to “TROUBLE-
SHOOTING DE-
TAILS” on page 8-36.
Monitor the opera-
tion of the sensors
and actuators in the
diagnostic mode. Re-
fer to “TROUBLE-
SHOOTING
DETAILS” on page
8-36 and “DIAGNOS-
TIC CODE TABLE”
on page 8-54. Check and repair.
01: Throttle position sensor (throttle angle)
30: Ignition coil
36: Fuel injector
FI diagnostic tool
90890-03182