General Information

The pressures and temperatures in the refrigerant circuit depend on the current operating conditions (such as engine RPM, coolant fan level 1, 2 or 3, engine temperature, A/C compressor on or off) as well as on the effects of outside influences (such as outside temperature, humidity, desired cooling output).

In vehicles with A/C Compressor Regulator Valve -N280-, the pressure is modified on the low pressure side by the -N280-.

On vehicles with an Electrical A/C Compressor -V470- the refrigerant circuit pressure (high and low-pressure sides) is regulated via the A/C compressor speed sensor.

On vehicles with an Electrical A/C Compressor -V470- on which the A/C system does not only cool the vehicle interior but also cools the components of the high-voltage system and is used as a heat pump to heat the vehicle interior, other conditions, pressures and temperatures in the refrigerant circuit apply (for example in the Audi Q7 e-tron). Use the Vehicle Diagnostic Tester in the"Guided Fault Finding"  function and refer to Refrigerant Circuit .

For this reason, values indicated in the following table are valid only as reference points. They are attained at an engine speed of 1500 to 2000 RPM and an ambient temperature of 20 °C (68 °F) after approximately 20 minutes.

The connections for the pressure gauge set intended for the pressure measurement are indicated on the vehicle specific refrigerant circuit. Refer to Refrigerant Circuit or.

At 20 °C (68 °F) with the engine not running, the pressure in the refrigerant circuit is 4.7 bar (68 psi). Refer to REFRIGERANT R134A VAPOR PRESSURE TABLE  (vapor pressure table).