Yamaha F400A 2022 - Page 183

Outboard motor troubleshooting
4-10
39
Oil pressure
sensor (Out of
specification)
“Check Engine” is displayed.
High engine idle speed.
Declining maximum engine
speed.
Check the oil pressure using
the YDIS.
7-1
Measure the oil pressure sen-
sor input voltage.
5-26
Measure the oil pressure sen-
sor output voltage.
5-26
Check for wiring continuity
between the oil pressure sen-
sor and the engine ECM.
A-10
42
Thermo sensor
(P) (Out of
specification)
“Check Engine” is displayed.
Set to 50 °C (122 °F) when
running.
<Engine speeds do not syn-
chronize>
Check the thermo sensor us-
ing the YDIS.
5-38
Measure the thermo sensor
input voltage.
5-38
Measure the thermo sensor
resistance.
5-38
Check for wiring continuity
between the thermo sensor
and the engine ECM.
A-14
43
Thermo sensor
(S) (Out of
specification)
“Check Engine” is displayed.
Set to 50 °C (122 °F) when
running.
<Engine speeds do not syn-
chronize>
Check the thermo sensor us-
ing the YDIS.
5-38
Measure the thermo sensor
input voltage.
5-38
Measure the thermo sensor
resistance.
5-38
Check for wiring continuity
between the thermo sensor
and the engine ECM.
A-14
56
Main power
supply (Irregu-
lar signal)
“Check Engine” is displayed.
Main relay is not turned off
even if the engine start switch
is OFF.
Battery discharges.
Check for wiring short be-
tween the engine start switch
and the engine ECM.
A-16
Check for wiring short be-
tween the electrical manage-
ment box and the engine
ECM.
A-16
Replace the electrical man-
agement box.
7-22
Trou-
ble
code
Item (Condi-
tion)
Symptom Checking steps
See
page