Fiat 1998 Marea Service Manual page 299

Marea- Marea Weekend
99 update
INJECTION NTC
°C
Q,
°c
-20 15971 40 1152
-10 9620 50 807
0 5975 60 576
10 3816 70 418
20 2502 80 309
25 2044 90 231
30 1679 100 176
KS1
B
T H 2 0
Copyright Fiat Auto
ft
INSTRUMENT
NTC
°C Q
Q
60 512-602
90 184-208
120 76-88
16v
ENGINE COOLANT TEMPERATURE SEN-
SOR
This sensor is fitted on the thermostat.
It consists of a brass casing which affords
protection for the resistive elements, compris-
ing two NTC type thermistors (Negative Tem-
perature Coefficient, where the electrical resis-
tance decreases as the temperature increases).
The two thermistors are distinctive and provide
information for the instrument panel (A) and
the engine management control unit (B), re-
spectively.
The reference voltage for the latter is 5 Volt:
since the control unit input circuit is designed
as a voltage divider, the reference voltage is
shared between a resistance in the control unit
and the actual sensor.
As a result, the control unit is capable of
evaluating the variations in the sensor resis-
tance through the changes in the voltage,
thereby obtaining information concerning the
temperature.
The table illustrates the sensor progress, which
can be measured by disconnecting the con-
nector and connecting an ohmmeter as shown
in the diagram.
Wiring connector
Engine
Fuel system
10.
29