Refrigerant Pressure Sensor / Switch: Description and Operation

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 between 0-5 volts. When the A/C refrigerant pressure is low, the signal value is near 0 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 engine control module (ECM) or powertrain control module (PCM) disables the compressor clutch under the following conditions:
A/C high side pressure is more than 2945 kPa (427 psi). The clutch will be enabled after the high side pressure decreases to less than 2069 kPa (300 psi). A/C low side pressure is less than 210 kPa (31 psi). The clutch will be enabled after the low side pressure increases to more than 258 kPa (37 psi).