Fiat 1996 Brava Service Manual page 278

Bravo-Brava igji 16v
9 8 range
11B
P4A27JJ04
Engine
Fuel system
10.
VEHICLE SPEED SENSOR
This sensor is positioned at the differential
output, by the left driveshaft coupling and
transmits information concerning the vehicle
speed to the speedometer: the signal is then
sent to the engine control unit.
The sensor is the Hall effect type and is cali­
brated so that a given distance corresponds
to each impulse: it is therefore possible to de­
termine the speed of the vehicle on the basis
of the frequency of the impulses.
POWER ASSISTED STEERING SENSOR
This sensor, fitted on the pump outlet high
pressure pipe, consists of a pressure switch
which closes when the hydraulic pressure
exceeds a set value corresponding to the
steering in the end of travel position: the in­
formation is used to managing the idle speed
control actuator in advance of the absorption
of power due to the steering.
DETONATION SENSOR
This is a piezoelectric type sensor fitted on
the cylinder block/crankcase, symmetrical in
relation to the pairs of cylinders 1 -2 and 3-4.
This position is determined by the need to
detect the onset of detonation in the same
way in all cylinders.
When the engine is knocking, vibrations of a
particular frequency are produced in the
cylinder block/crankcase which are trans­
formed, by the sensor, into a voltage signal
which is proportional to their intensity.
Wiring connector
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