Self-Diagnostic Function Table; Fail-Safe Action Table - Yamaha MT-03 Service Manual

EAS27380

SELF-DIAGNOSTIC FUNCTION TABLE

If the ECU detects an abnormal signal from a sensor while the vehicle is being driven, the ECU illu-
minates 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.

FAIL-SAFE ACTION TABLE

Self-diagnostic function
Fault
Item
code No.
Crankshaft position
12
sensor
Intake air pressure
13 sensor (open or short
circuit)
Intake air pressure
sensor
14
Throttle position sensor
15
(open or short circuit)
Throttle position
16
sensor (stuck)
Broken or discon-
19 nected blue/black
lead of the ECU
Coolant temperature
21
sensor
Intake air temperature
22
sensor
Lean angle cut-off
30 switch (latch up
detected)
Faulty ignition
33
Lean angle cut-off
41 switch (open or
short circuit)
Speed sensor,
neutral switch
42
Fuel system voltage
(monitor voltage)
43
Error in writing the
amount of CO
44
adjustment on
EEPROM
Symptom
No normal signals are
received from the sensor.
Open or short circuit is
detected.
Intake air pressure sensor
hose is clogged or discon-
nected, causing the constant
application of atmospheric
pressure to the sensor.
Open or short circuit is
detected.
The throttle position sensor
is detected stuck.
Open circuit in the input line
(blue/black) of the ECU is
detected.
Open or short circuit is
detected.
Open or short circuit is
detected.
The motorcycle has
overturned.
Open circuit is detected in
the primary lead of the
ignition coil.
Open or short circuit is
detected.
No normal signals are
received from the speed
sensor or an open or short
circuit is detected in the
neutral switch.
The ECU is unable to
monitor the battery voltage
(open circuit in the wire to
the ECU).
An error is detected while
reading or writing on
EEPROM (CO adjustment
value).
7-20
FUEL INJECTION SYSTEM
Fail-safe action
—
• Fixes the intake air pres-
sure to 101 kPa
(760 mmHg, 29.9 inHg).
• Fixes the intake air pres-
sure to 101 kPa
(760 mmHg, 29.9 inHg).
• Fixes the throttle position
sensor to fully open.
• Fixes the throttle position
sensor to fully open.
—
• Fixes the coolant tempe-
rature to 80 °C (176 °F).
• Fixes the intake air tem-
perature to 20 °C (68 °F).
—
—
—
• Fixes the gear to the top
gear.
• Fixes the battery voltage
to 12 V.
—
Startability Driveability
No No
Yes Yes
Yes Yes
Yes Yes
Yes Yes
No No
Yes Yes
Yes Yes
No No
No No
No No
Yes Yes
Yes Yes
Yes Yes