Evinrude E-tec 75 HP, Service Manual

Page: 88 / 344

88
ENGINE MANAGEMENT MODULE (EMM)
SENSORS AND FUNCTIONS
Barometric Pressure Sensor
Supplies the
EMM
with barometric pressure read-
ing to compensate for changes in altitude and air
density.
If the BP sensor is out of the expected range
(below 13.3 KPa or above 119.0 KPa), or the sen-
sor or circuit fails, the
EMM:
If the BP sensor is below expected range (below
70 KPa), the
EMM:
If the BP sensor is above expected range (above
105 KPa), the
EMM:
External Sensors
The
EMM
provides a 5 V DC signal for sensor cir-
cuits. It monitors all sensor voltage inputs and
compares them to predetermined acceptable
ranges. Inputs that fall outside of the acceptable
range initiate service codes.
Air Temperature Sensor
Monitors the air temperature at the throttle body.
The air temperature sensor is a negative tempera-
ture coefficient (NTC) thermistor. As temperature
increases, the resistance of the sensor decreases
resulting in a lower voltage reading at the
EMM.
Temperature decreases result in a resistance
increase and a higher voltage reading at the
EMM
.
If the AT sensor voltage is out of the expected
range, or the sensor or circuit fails, the
EMM:
Engine Temperature Sensor
Monitors temperature at the top of cylinder head.
The sensor is a negative temperature coefficient
thermistor (NTC). It provides engine temperature
information to the
EMM.
The
EMM
uses this infor-
mation to control engine operation and to activate
the overheat warning system.
If engine temperature exceeds 212°F (100°C), the
EMM
:
If engine temperature exceeds 248°F (120°C), the
EMM:
The outboard will not restart, after a temperature
related SHUTDOWN, until the engine temperature
returns to normal. Refer to
SHUTDOWN MODE
on p. 92.
If sensor values are below -15°F (-26.1°C) or
above 331°F (166.5°C), the
EMM:
If sensor values are below -4°F (-20°C), the
EMM:
If engine does not reach operating temperature
(104°F / 40°C below 2300 RPM), the
EMM
:
Stores a service code 44
Initiates
EMM
SENSOR FAULT LED
Stores a service code 45
Initiates
EMM
SENSOR FAULT LED
Stores a service code 46
Initiates
EMM
SENSOR FAULT LED
Stores a service code 47
Initiates
EMM
SENSOR FAULT LED
Activates
S.A.F.E.
Stores a service code 43
(engine temperature above expected range)
Initiates
EMM
NO OIL / OVERHEAT LED
Initiates
SystemCheck
TEMP/HOT light
Activates SHUTDOWN
Stores a service code 31
Flashes
EMM
NO OIL / OVERHEAT LED
Flashes
SystemCheck
TEMP/HOT light
Stores a service code 41
Initiates
EMM
SENSOR FAULT LED
Stores a service code 42
(engine temperature below expected range)
Initiates
EMM
SENSOR FAULT LED
Stores a service code 58
(engine not reaching operating temperature)