Alternate Operation Control (Fail-Safe Action); Fail-Safe Action Table - Yamaha XT660R 2004 Service Manual

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EAS00901
Checking for a defective engine trouble warning light bulb
The engine trouble warning light comes on for 1.4 seconds after the main switch is turned to "ON" or
when the start switch is pushed. If the warning light does not come on under these conditions, the
warning light bulb may be defective.
Main switch Main switch
off
Engine trouble Light
warning light off
EAS00902

ALTERNATE OPERATION CONTROL (FAIL-SAFE ACTION)

If the ECU detects an abnormal signal from a sensor while the motorcycle is being driven, the ECU
illuminates the engine trouble warning light and it provides the engine with alternate operating
instructions, according to the 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 the alternate operating instruc-
tions that enable the engine to continue to operate or stop operating, depending on the conditions.
The ECU applies the fail-safe actions in two ways: one in which the sensor output is set to a pre-
scribed value, and the other in which the ECU directly operates an actuator. Details on the fail-safe
actions are given in the table below.

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 sensor
16
(stuck)
Broken or discon-
19 nected blue/black lead
of the ECU
Coolant temperature
21
sensor
Intake air temperature
22
sensor
email: info@motomatrix.co.uk
FUEL INJECTION SYSTEM
on
Light on for 1.4 Light
seconds off
Initialized
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.
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 tempera-
ture to 80 °C (176 °F).
• Fixes the intake air tem-
perature to 20 °C (68 °F).
7 - 4
FI
Startability Driveability
No No
Yes Yes
Yes Yes
Yes Yes
Yes Yes
No No
Yes Yes
Yes Yes