Fiat 1998 Marea Weekend, Service Manual

Page: 169 / 846

Marea-Marea Weekend^
1998 range
lev
Engine
Fuel system
10.
NTC INJECTION
c
Q
-20 15970
-10
9620
0 5975
10 3816
20 2500
25 2044
30 1679
C Q
40 1150
50 807
60 576
70
418
80 309
90 231
100 176
INSTRUMENT
NTC
c
n
60
90
120
512-602
184-208
76-88
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.
Connection to coolant temperature gauge
on instrument panel
Wiring connector
The numbers in boxes indicate the corre-
sponding control unit pins.
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