A/C Pressure Sensor
WARNING: This page is about a different car, the 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, 2003 Chevrolet Monte Carlo, and 2003 Chevrolet Impala. However, it is still accessible from the selected car via links, so may be relevant.
The Powertrain Control Module (PCM) monitors the high side refrigerant pressure via an A/C refrigerant pressure sensor. The A/C refrigerant pressure sensor is a 3-wire piezoelectric pressure transducer. A 5-volt reference, low reference, and signal circuits enable the sensor to operate. The A/C pressure signal can be 0-5 volts. When the A/C refrigerant pressure is low, the signal value is near zero volts. When the A/C refrigerant pressure is high, the signal value is near 5 volts. The A/C refrigerant pressure sensor protects the A/C system from operating when an excessively high or low-pressure condition exists. The PCM disables the compressor clutch under the following conditions:
- A/C pressure is more than 432 psi (2979 kPa). The clutch enables after the pressure decreases to less than 219 psi (1510 kPa).
- A/C pressure is less than 27 psi (186 kPa). The clutch enables after the pressure increases to more than 30 psi (207 kPa).