A/C Refrigerant Pressure Sensor

WARNING: This page is about a different car, the 2002 Oldsmobile Intrigue. 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 varied 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 432 psi (2979 kPa), the PCM will turn off the A/C compressor clutch until the pressure lowers to 219 psi (1510 kPa). If line pressure falls below 27 psi (186 kPa), the PCM will turn off the A/C compressor clutch until the pressure raises to 30 psi (207 kPa). 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 monitors the A/C pressure by monitoring the 5 volt signal on the A/C refrigerant pressure sensor signal circuit. This circuit is how the PCM monitors HVAC pressures. Ground for the A/C refrigerant pressure sensor is provided by the low reference circuit.