Fiat 1996 Brava Service Manual page 354

Bravo-Brava ty™ Engine
98 range Fuel system
10.
Control of exhaust fumes
Through this function the injection control unit limits any exhaust fumes which could occur during
strong acceleration.
In order to satisfy this requirement, the control unit processes the signals supplied by the accelerator
pedal potentiometer, the rpm sensor and the intake air quantity sensor (flow meter) and operates the fu­
el pressure regulator and the injectors to correctly meter the quantity of fuel to be injected.
Control of exhaust gas recirculation
On the basis of the signals supplied by the rpm, intake air quantity, engine coolant temperature and ac­
celerator pedal position sensors, the injection control unit calculates the operating times for the EGR
solenoid valve so that the exhaust gases are partly recirculated in certain engine operating conditions.
Control of engagement of air conditioning system
The injection control unit manages the operation of the air conditioning system compressor electro­
magnet coupling following a logic aimed at preventing operating conditions which would adversely af­
fect engine performance.
When the compressor is switched on, the injection control unit increases the quantity of fuel during
idling so that the engine can meet the request for more power and interruptsthe supply to the compres­
sor in the following conditions:
- request for high power for the engine (strong acceleration);
- excessive engine coolant temperature.
Control of engine immobilizer function
The system is equipped with an engine immobilizer function. This function is achieved through the
presence of a special control unit (Fiat CODE), capable of dialogue with the injection control unit and
an electronic key, with a special transmitter for sending a recognition code.
Each time the key is turned to the OFF position, the Fiat CODE system completely deactivates the injec­
tion control unit.
When the ignition key is placed in the ON position, the following operations take place in order:
1. the injection control unit (whose memory contains a secret code) sends the Fiat CODE control unit a
request for the latter to send the secret code to deactivate the immobilizer function;
2. the Fiat CODE control unit responds by only sending the secret code after having, in turn, received
the recognition code transmitted by the ignition key;
3. the recognition of the secret code allows the de-activation of the injection control unit immobilizer
function and normal operation to be resumed.
Autodiagnosis
The complete electronic fault diagnosis of the injection system can be carried out by connecting the
special equipment (EXAMINER or SDC station) to the diagnostic socket.
The system is also equipped with an autodiagnostic function which recognizes, memorizes and signals
any failures.
If a fault is detected at the sensors or actuators, the signal reconstruction (recovery) strategies are imme­
diately activated to ensure the operation of the engine at an acceptable level. The vehicle can therefore
be driven to a Service Centre to have the appropriate repairs carried out.
Copyright by Fiat Auto
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