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 powertrain control module (PCM) or engine control module (ECM) disables the compressor clutch under the following conditions:

A/C high side pressure is more than 2997 kPa (435 psi). The compressor clutch will be enabled after the high side pressure decreases to less than 1998 kPa (290 psi). A/C low side pressure is less than 180 kPa (26 psi). The clutch will be enabled after the low side pressure increases to more than 248 kPa (36 psi).