Refrigerant Pressure Sensor / Switch: Description and Operation

An electronic A/C pressure sensor is mounted in the liquid line (between the compressor and the condenser). Its output to the ECM is variable and is dependent upon pressure inside the line. A higher pressure results in a higher voltage output. The ECM constantly monitors A/C system pressure to:
1. Disengage the A/C clutch if the pressures are high (2700 kPa (430 psi).
2. Disengage the A/C clutch if pressures are too low (below 44 psi).
3. Boost idle air control to compensate for A/C load at idle.
4. Control cooling fan operation.
^ The pressure sensor is not repairable, if it fails, it must be replaced.