Skylark L4-138 2.3L DOHC VIN D MFI QUAD 4 (1989)
Refrigerant Pressure Sensor / Switch: Description and Operation
A/C PRESSURE SENSOR
The A/C pressure sensor provides a signal to the ECM which indicates varying high side refrigerant pressure between approximately 0.0 psi to 450 psi.
The ECM uses this input to determine A/C compressor load on the engine to help control idle speed with the IAC Valve. The A/C pressure sensor
electrical circuit consist of a 5.0 volt reference line, a ground, and a signal wire to the ECM. The signal is a voltage that varies from approximately 0.1
volts at 0.0 psi to 4.9 volts at 450 psi or more. A problem with the A/C pressure circuits or sensor should set a Code 66 and will make the A/C
compressor inoperative.
