A/C Pressure Sensor

AIR CONDITIONING PRESSURE SENSOR

A/C Pressure Sensor Output Voltage VS Pressure Chart:

Typical Air Conditioning Pressure Sensor:

The Air Conditioning Pressure (A/C pressure) sensor (Figure 20) is located in the high pressure (discharge) side of the air conditioning A/C system. The A/C pressure sensor provides a voltage signal to the Powertrain Control Module (PCM) that is proportional to the A/C pressure. The PCM uses this information for A/C clutch control, fan control and idle speed control.

The A/C pressure transducer monitors the compressor discharge pressure and communicates with the Powertrain Control Module (PCM). The PCM will interrupt A/C compressor operation in the event that the A/C pressure transducer indicates high system discharge pressures. It is also used to sense no or low charge conditions. If the pressure is below a predetermined value for a given ambient temperature, the PCM will not allow the clutch to engage.
- The A/C pressure transducer is mounted on a Schrader valve-type fitting on the A/C compressor to condenser discharge line.
- A valve depressor, located inside the threaded end of the A/C pressure transducer, presses on the Schrader valve stem and allows the A/C pressure transducer to monitor the compressor discharge pressure.
- When the compressor discharge pressure rises, the PCM will interrupt the A/C compressor clutch coil circuit and disengage the A/C compressor. When the pressure drops, the PCM will enable the A/C compressor circuit.
- It is not necessary to discharge the refrigerant system to remove the A/C pressure cut-off switch.