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) disables the compressor clutch under the following conditions:

• The A/C high side pressure is more than 2,929 kPa (425 psi).
• The clutch will be enabled after the high side pressure decreases to less than 1,376 kPa (200 psi).
• A/C low side pressure is less than 269 kPa (39 psi).
• The clutch will be enabled or will allow engagement again after the low side pressure increases to more than 296 kPa (43 psi).