Refrigerant Pressure Sensor
WARNING: This page is about a different car, the 2009 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.
The refrigerant system is protected against excessively high or low pressures by the refrigerant pressure sensor, located on the liquid tank attached to the condenser. If the system pressure rises above or falls below the specifications, the refrigerant pressure sensor detects the pressure inside the refrigerant line and sends the voltage signal to the ECM. The ECM then ceases to supply power to the A/C relay which disengages and stops the compressor when pressure on the high pressure side (as detected by refrigerant pressure sensor) is over approximately 2,746 kPa (28 kg/cm2 , 398 psi), or below approximately 120 kPa (1.22 kg/cm2 , 17.4 psi).