Fiat Bravo Service Manual page 239

Bravo-Brava 0
gB|16v
Engine
Fuel system
10.
VEHICLE SPEED SENSOR
The sensor is positioned on the differential
outlet, by the left drive shaft coupling and
transmits the information relating to the vehi­
cle speed to the control unit: the signal is also
used for the operation of the speedometer.
The sensor is the Hall effect type (see "engine
timing sensor" paragraph) and it is calibrated
so that for each impulse there is a corre­
sponding travel of one metre: on the basis of
the frequency of the impulses it is therefore
possible to know the speed of the vehicle.
Wiring connector
DETONATION SENSOR
This sensor is the piezoelectric type and is fit­
ted on the engine crankcase in a symmetrical
position in relation to the pairs of cylinders
1-2 and 3-4.
This position is determined by the need to
detect the start of detonation similarly for all
cylinders.
When there is detonation, vibrations of a par­
ticular frequency are created in the crankcase
which are transformed by the sensor into a si­
gnal whose voltage is proportional to their
intensity.
Wiring connector
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