Yamaha YW125Y_ Utility Trailer User Manual


 
6-5
FI
EAS00902
SELF-DIAGNOSTIC FANCTION TABLE
If the ECU detects an abnormal signal from a sensorwhile the vehicle is being driven, the ECU
illuminates the engine trouble warning light and provides the engine with alternate operating instruc-
tions that are appropriate for the type of malfunction.
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 to operate or stop operating, depending on the conditions.
The ECU takes fail-safe actions in two ways: one in which the sensor output is set to a prescribed
value, and the other in which the ECU directly operates an actuator. Details on the fail-safe actions
are aiven in the table below.
Self-diagnostic fanction table
EAS00901
CHECKING FOR A DEFECTIVE ENGINE TROUBLE WARNING LIGHT BULB
The engine trouble warning light comes on for 2 seconds after the main switch has been turned “ON”
and when the start switch is being pushed. If the warning light does not come on under these condi-
tions, the warning light bulb may be defective.
Crankshaft position sensor
Intake air pressure sensor
(open or short circuit system)
Throttle position sensor
(open or short circuit)(stuck)
Broken or disconnected
sidestand lead of the ECU
Intake air temperature sensor
O
2
sensor
Engine temperature sensor
Faulty ignition
ISC (idle speed control) valve
(stuck fully open)
Fault
code No.
Item Symptom
Engine
startability
Vehicle
driveability
No normal signals are received from the
crankshaft position sensor.
Intake air pressure sensor-open or short
circuit detected.
Faulty intake air pressure sensor system.
Throttle position sensor-open or short cir-
cuit detected.
A stuck throttle position sensor is de-
tected.
Open circuit in the input line (sidestand) of
the ECU is detected.
Intake air temperature sensor-open or short
circuit is detected.
No normal signal is received from the O
2
sensor.
Engine temperature sensor-open or short
circuit detected.
Open circuit detected in the primary lead
of the ignition coil.
Engine speed is high when the engine is
idling.
Unable
Able
Able
Unable
Able
Able
Able
Unable
Able
Unable
Able
Able
Unable
Able
Able
Able
Unable
Able
12
13
14
15
16
19
22
24
28
33
37
FUEL INJECTION SYSTEM
Main switch
OFF
Main switch
ON
Engine trouble
warning light
Light
OFF
Light ON for
2 seconds
Light
OFF
Intialize
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