Fiat 1998 Marea Weekend, Service Manual

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Marea- Marea Weekend ft
Engine
99 range
Fuel system
10.
MANAGEMENT OF THE CLIMATE CONTROL SYSTEM
The injection/ignition control unit is functionally connected to the climate control system, as follows:
1. it receives the request to switch on the compressor and operates the various interventions (additional
air);
2. it gives the go ahead to switch on the compressor when the strategy conditions are verified;
3. it receives information on the state of the four stage pressure switch and operates the various interven-
tions (operation of the radiator fan).
As far as point 1 is concerned, if the engine is idling, the control unit increases the air flow rate, altering
the position of the butterfly in advance of the compressor being switched on and conversely returns the
butterfly to its normal position after the compressor is switched off.
The engine idle speed is also increased for the entire time the compressor is activated (engine warm: 900
rpm).
As far as point 2 is concerned, the control unit automatically controls the switching off of the compressor:
- for several seconds (timed disengagement):
- in high engine power requirement conditions (fierce acceleration);
- during vehicle take-off;
- as long as the following critical conditions exist:
- temperature of the engine coolant above a pre-set level (engine overheated);
- engine speed below 700 rpm
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