Refrigerant Pressure Sensor
WARNING: This page is about a different car, the 2008 Infiniti M45 and 2008 Infiniti M35. 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. 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. ECM makes the A/C relay go OFF and stops the compressor when pressure on the high-pressure side detected by refrigerant pressure sensor is over about 3,119 kPa (31.8 kg/cm2 , 452 psi), or below about 118 kPa (1.2 kg/cm2 , 17 psi).