Management Of The Fiat Code Ant-Theft Function; Rotation Speed Restricter; Electric Fuel Pump Operation; Operation Of The Injectors - Fiat 1998 Marea Service Manual

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Rotation speed restricter

This strategy restricts the maximum speed which can be reached by the engine enabling the cut-off. There
are two different cut-off levels:
- static restricter (the engine speed approaches the level slowly): maximum speed = 6670 rpm;
- dynamic restricter (the speed approaches the level rapidly): maximum speed = 6500 rpm;

Electric fuel pump operation

The electric fuel pump is operated by the engine control unit by means of a relay.
The pump cuts out:
- if the engine speed goes below 50 rpm
- after a certain period (about 5 seconds) with the ignition key in the ON position without the engine
being started up (timed go ahead);
- if the inertia switch has been operated.

Operation of the injectors

The operation of the injectors is the phased sequential type. However, during cold starting the injectors are
operated in parallel up to a certain temperature.
The phasing of the injectors can vary according to the engine speed.

MANAGEMENT OF THE FIAT CODE ANT-THEFT FUNCTION

The system is equipped with an anti-theft function. This function is achieved thanks to the presence of a
special control unit (FIAT CODE) capable of conversing with the engine 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 engine
control unit.
When the key is turned to the ON position, the following operations take place in the order given:
1. the engine control unit (whose memory contains a secret code) sends the FIAT CODE control unit a
request 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 deactivation of the engine control unit immobilizer func-
tion and normal operation is resumed.
NOTE If the FIAT CODE anti-theft system is fitted, DO NOT CARRY OUT the test, during the fault diag-
nosis, using another engine control unit. In effect, in such circumstances, the FIA T CODE control
unit would transfer the (unrecognized) code to the test control unit which could then no longer
be used on other vehicles.
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