Alero L4-144 2.4L DOHC VIN T SFI (2000)
Refrigerant Pressure Sensor / Switch: Description and Operation
The A/C refrigerant pressure sensor provides a signal to the PCM which indicates varying high side refrigerant pressure between approximately 0 psi and
450 psi.
The PCM uses this input in order to determine the A/C compressor load on the engine in order to help control idle speed with the IAC valve.
The A/C refrigerant pressure sensor circuit consists of a 5 volt reference line and a ground line, both provided by the PCM, and a signal line to the PCM.
The signal is a voltage that varies from approximately 0.1 volt at 0 psi, to 4.9 volts at 450 psi or more. A problem in the A/C refrigerant pressure circuits
or sensor may set a DTC P0530 and will make the A/C compressor inoperative.
