Refrigerant Pressure Sensor
WARNING: This page is about a different car, the 1995 Chevrolet Caprice. However, it is still accessible from the selected car via links, so may be relevant.
The refrigerant pressure sensor is attached to compressor and condenser hose. It senses high side pressures and sends a signal to PCM. If high side pressure exceeds 429 psi (30.1 kg/cm2 ), PCM will disable compressor.