Fail-Safe Control - Yamaha F150A Service Manual

Fail-safe control

If the electrical components malfunction, the engine ECM controls the ignition and fuel injection as
shown in the table.
Trouble
code
13 Pulser coil
15 Engine temperature sensor
18 TPS
19 Battery voltage
23 Air temperature sensor
28 Shift position switch
29 Air pressure sensor
37 Intake air passage
39 Oil pressure sensor
45 Shift cut-off switch
46 Thermoswitch
86 Immobilizer (Y-COP)
*1. Control mode when the part malfunctions.
Item
No signal is sent from one of two sensors 4 or more
consecutive times.
Open or short circuit in the engine temperature sensor
circuit.
Output voltage is less than 0.18 V or more than 4.93 V.
When the engine starts: Set to 5 °C (41 °F), 20 °C
(68 °F), or 40 °C (104 °F) depending on the signal
from the air temperature sensor. *1
Open or short circuit in the TPS circuit
Output voltage is less than 0.3 V or more than 4.7 V.
Determines the fully closed position of the throttle
based on the signal from the air pressure sensor. *1
Voltage is less than 12 V for 2 minutes, even when
engine speed is more than 2000 r/min.
Open or short circuit in the air temperature sensor
circuit.
Output voltage is less than 0.1 V or more than 4.61 V.
Set to 40 °C (104 °F). *1
Cranking while in gear.
Cranking while the shift position circuit is open-
circuited.
Open or short circuit in the air pressure sensor circuit.
Output voltage is less than 0.2 V or more than 4.5 V.
Temporarily sets air pressure levels based on the
engine speed and the TPS signal. *1
The shift position switch is off, the throttle is fully
closed, the ISC valve is fully closed, and the engine
speed is more than 1200 r/min.
Open or short circuit in the oil pressure sensor circuit.
Output voltage is less than 0.3 V or more than 4.8 V.
Output voltage is more than 4.5 V, the switch is ON
when the engine is started, or both the shift cut-off
switch and shift position switch are ON for 5 seconds.
Not detected
Open or short circuit in the Y-COP circuit.
Communication error continues for more than 3
seconds.
Trouble conditions to be detected
2-6
Electronic control system
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