Functionality check of the A/C system's pressure sensor
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Functionality check of the A/C system's pressure sensor
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Warning
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Read through the following safety regulations before you start working on the A/C system.
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Wear protective glasses and impermeable gloves, since there is a risk of burn and frost injuries.
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If the skin comes into contact with the refrigerant, the exposed areas should be bathed in cold water and treated like a burn.
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Should the coolant get into the eyes, they must be rinsed thoroughly with water for at least 10 minutes.
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Refrigerant must not intentionally be released into the atmosphere. If, however, the refrigerant is unintentionally released in the premises, open and ventilate well before continuing work.
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Gases that are formed when heating a refrigerant are a health hazard and can have a serious effect on the lungs.
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Work should commence as soon as possible after emptying the A/C system as residual oil may emit refrigerant vapour that could collect and leak out if the work is delayed.
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Smoking and open flames must not occur when handling refrigerants.
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Refrigerant containers must not be exposed to heating, because the pressure will then increase resulting in the risk of explosion.
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1.
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Connect the diagnostic tool
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2.
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Remove the connector from the Fan Variant.
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3.
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Shut the bonnet until the catch locks.
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Warning
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Operating with the diagnostic tool must be done from inside the cabin for safety reasons.
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Important
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Ensure the engine is cold before starting the test.
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5.
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Read the A/C pressure by, via the diagnostic tool, selecting 9-3(9440),
Body,
Heating, Ventilation and A/C,
Air Conditioning. Select Read Values
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6.
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Start the engine.
Regulate to max fan speed (ventilation fan), max. heating and distribution mode VENT and RECIRC.
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Note
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The pressure should be measured in absolute pressure, bar
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7.
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Await the pressure build up. For approved operation the pressure build up should cease at 27 bar, i.e. the compressor switches off. The pressure build up should automatically start again when the pressure drops below 22 bar, i.e. the compressor switches on.
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Warning
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If the pressure exceeds 30 bar or if the engine coolant temperature is too high,
turn off the engine!
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9.
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With approved operation, turn off the engine.
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10.
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Turn ON the ignition. Allow the pressure to drop to 20 bar.
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11.
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Open the bonnet. Connect the connector to the fan variant.
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12.
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Note in the report the read values for the compressor's cut-in and turn-off pressure. Reset the car and check the A/C operation.
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