DTC P0530: A/C Refrigerant Pressure Sensor Circuit: Description
WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
Air Conditioning (A/C) pressure sensor is a transducer that varies resistance according to changes in high side refrigerant pressure. ECM measures signal voltage from A/C refrigerant pressure sensor, which is a reduced value of ECM 5-volt reference. Maximum voltage ranges of the sensor are around 0.25 volt at 14.7 psi and 4.75 volts at 493 psi. Sensor input is primarily used by ECM to determine when to turn on cooling fans. Sensor input also aids in determining acceptable low/high refrigerant pressure for A/C operation and A/C idle speed control. DTC sets when A/C pressure sensor signal voltage at ECM is more than or less than calibrated value.