CITROEN 2005 C4-XSARA-XSARA PICASSO BERLINGO Owner's Manual page 450

CHECKING THE EFFICIENCY OF THE AIR CONDITIONING SYSTEM
Principal problem
The aircon compressor makes an abnormal
noise
Aircon circuit diagnosis table
Symptom
The clutch of the aircon compressor
remains engaged
The clutch of the aircon compressor
remains engaged and slips
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Possible causes
Incorrect adjustment of the aircon compressor
clutch
Aircon fluid quantity
Aircon compressor defective
Lack of aircon fluid in the aircon circuit
Aircon compressor valves defective
Aircon compressor clutch
Auxiliaries drive belt