Refrigerant Temperature Sensor

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NOTE:

A refrigerant temperature sensor (a temperature sensor without pressure evaluation) is currently not installed in Volkswagen/Audi.

Switching pressures, removing and installing switches as well as switch arrangement and version. Use the Vehicle Diagnostic Tester in the A/C system"Guided Fault Finding" function and refer to Refrigerant Circuit (vehicle-specific Service Information).

The refrigerant temperature sensor (with temperature-dependent resistance) is installed, for example, in the high pressure line in vicinity of the A/C compressor.

Fig 1: Identifying Refrigerant Temperature Sensor -G454-
Courtesy of AUDI OF AMERICA, LLC
In the refrigerant circuit, there is a direct correlation between temperature and pressure. Should there be too little refrigerant in the refrigerant circuit, the temperature in the refrigerant circuit increases more steadily on the high pressure side than intended for this pressure when the A/C system is operating.

NOTE:

The respective control modules, for example, the Front A/C Display Control Head -E87- or the Climatronic Control Module -J255- evaluates the pressure and temperature in the refrigerant circuit and switches the A/C compressor off, if the temperature exceeds the value that was stored for this pressure. Use the Vehicle Diagnostic Tester in the A/C system"Guided Fault Finding" function and refer to Refrigerant Circuit (vehicle-specific Service Information).