A/C Refrigerant Pressure Sensor

WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

The A/C system is protected by the A/C refrigerant pressure sensor. The sensors output to the PCM is variable and is dependent upon pressure inside the line. A higher pressure results in a higher voltage output. The A/C pressure is constantly monitored in order to allow the A/C compressor clutch to disengage as needed. If line pressures climb above 2826 kPa (410 psi) or fall below 207 kPa (30 psi), the PCM will turn off the A/C compressor clutch.

A 5-volt reference signal is sent out over the 5-volt reference circuit, from the PCM, to the A/C refrigerant pressure sensor. Voltage is dropped across the sensor and the PCM monitors the remaining voltage on the A/C refrigerant pressure sensor signal circuit. Ground for the A/C refrigerant pressure sensor is provided by the low reference circuit.