A/C Refrigerant Pressure Sensor

WARNING: This page is about a different car, the 2002 Pontiac Firebird and 2002 Chevrolet Camaro. However, it is still accessible from the selected car via links, so may be relevant.

The A/C system is protected by the A/C refrigerant pressure sensor. The sensors output to the PCM is variable and is dependent upon pressure inside the line. A higher pressure results in a higher voltage output. The A/C pressure is constantly monitored in order to allow the A/C compressor clutch to disengage as needed. If line pressures climb above 414 psi (2854 kPa) or fall below 35 psi (241 kPa), the PCM will turn off the A/C compressor clutch. When high side pressures drop back down between 39-250 psi (269-1724 kPa), the PCM will allow the A/C compressor to operate.

A 5 volt reference signal is sent out over the 5 volt reference circuit, from the PCM, to the A/C refrigerant pressure sensor. The PCM reads the A/C pressure by monitoring the voltage on the A/C refrigerant pressure sensor signal circuit. Ground for the A/C refrigerant pressure sensor is provided by the low reference circuit.