Engine Coolant Temperature Sensor - Fiat 1998 Marea Service Manual

Marea-Marea
1998 range
NTC INJECTION
c
Q C
-20 15970 40
-10 9620 50
5975
0 60
10 3816 70
20 2500 80
25 2044
90
30 1679 100
Connection to coolant temperature gauge
on instrument panel
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INSTRUMENT
NTC
Q
c
n
1150
60 512-602
807
90 184-208
576
120
76-88
418
309
231
176
lev
ENGINE COOLANT TEMPERATURE
SENSOR
(Jaeger 402.183.01)
(Elth 2690350)
The sensor is fitted to the thermostat case. It
consists of a brass case, which protects the
actual resistance element: two NTC thermis-
tors (standing for Negative Temperature Co-
efficient because sensor electrical resistance
decreases in inverse proportion to tempera-
ture).
The two NTC unuts are separate and send
temperature information to a special indicator
on the instrument panel and to the injec-
tion-ignition control unit.
The reference voltage is 5V for the injection
system NTC element; since this circuit is de-
signed as a voltage divider, the voltage is dis-
tributed between a resistance present in the
ECU and the sensor N.T.C. resistance. The
ECU is therefore able at any moment to as-
sess sensor resistance changes through volt-
age changes and thus obtain information on
intake air temperature.
1. NTC for injection system
2. NTC for indicator on instrument panel
Recovery
The last reading is adopted or a fixed value of
80 °C if intake air temperature exceeds a cer-
tain value
Mixture concentration self-adaption is inhib-
ited.
The radiator fan is activated.
Idle self-adaption is inhibited.
Checking resistance
The table alongside shows sensor resistance
values at different temperatures. These may be
measured by disconnecting the connector and
connecting an ohmmeter to the sensor termi-
nals.
Removing-refitting
Disconnect electrical connection and remove
the sensor.
E
Tightening torque 2.2 daNm.
Wiring connector
The numbers in boxes indicate the corre-
sponding control unit pins.
Engine
Fuel system
10.
35