A/C Refrigerant Pressure Sensor

The A/C system is protected by the A/C refrigerant pressure sensor. The sensor is mounted in the evaporator tube between the evaporator and the condenser. The sensor 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.