Alternate Instructions Operation Control; Fail-Safe Action; Fail-Safe Action Table - Yamaha XP500 Service Manual

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 has been turned to
"ON" and when the start switch is being pushed. If the warning light does not come on under these
conditions, the warning light bulb may be defective.
Main switch
OFF
Engine trouble Light
warning light off
EAS00902
ALTERNATE INSTRUCTIONS OPERATION CONTROL (FAIL-SAFE ACTION)
If the ECU (engine) detects an abnormal signal from a sensor while the vehicle is being driven, the
ECU (engine) illuminates the engine trouble warning light and provides the engine with alternate
operating instructions that are appropriate for the type of malfunction.
When an abnormal signal is received from a sensor, the ECU (engine) processes the specified val-
ues 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 condi-
tions.
The ECU (engine) takes 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 (engine) directly operates an actuator. Details on the
fail-safe actions are given in the table below.
EAS00903

FAIL-SAFE ACTION TABLE

Fault
Item
code No.
Crankshaft position
12 sensor
Intake air pressure
13 sensor (open or short
14 circuit) (pipe system)
Throttle position sensor
15
(open or short circuit)
16
(stuck)
Sidestand switch (open
19 circuit in wire to ECU
(engine))
Coolant temperature
21
sensor
Intake temperature
22
sensor
O sensor (inactive)
2
24
Faulty ignition
33
FUEL INJECTION SYSTEM
Main switch
ON
Light on for 1.4 Light
seconds off
Initialize
Symptom
No normal signals are
received from the crankshaft
position sensor.
Intake air pressure sensor-
open or short circuit detected.
Faulty intake air pressure sen-
sor system.
Throttle position sensor-open
or short circuit detected.
Open circuit is detected in the
input line from the sidestand
switch to the ECU (engine).
Coolant temperature sensor-
open or short circuit detected.
Intake temperature sensor-
open or short circuit detected.
No normal signals are
received from the O
Open circuit detected in the
primary lead of the ignition
coil.

Fail-safe action

--
Fixes the intake air pressure
to 101.12 kPa
2
(1.01 kgf/cm , 14.4 psi).
Fixes the throttle position
sensor to fully open.
-- (No start)
Fixes the coolant tempera-
ture to 80 °C (176 °F).
Fixes the intake tempera-
ture to 20 °C (68 °F).
--
sensor.
2
--
7 - 4
FI
Engine start- Vehicle drive-
ability ability
Unable Unable
Able Able
Able Able
Unable Unable
Able Able
Able Able
Able Able
Unable Unable