Refrigerant Pressure Sensor

WARNING: This page is about a different car, the 2018 Land Rover Discovery and 2017 Land Rover Discovery. However, it is still accessible from the selected car via links, so may be relevant.

The refrigerant pressure sensor is located in the high pressure refrigerant line between the condenser and the Thermostatic Expansion Valve (TXV). For additional information, refer to: AIR CONDITIONING .

The Automatic Temperature Control Module (ATCM) supplies a 5V reference voltage to the refrigerant pressure sensor and receives a return signal voltage related to system pressure.

The ATCM uses the signal from the refrigerant pressure sensor to protect the refrigerant system from extremes of pressure. The signal is also used to calculate the Air Conditioning (A/C) compressor load on the engine. The ATCM transmits the Air Conditioning (A/C) compressor load value for use in controlling the speed of the engine cooling fan. The value is transmitted to the Powertrain Control Module (PCM), via the High Speed (HS) Controller Area Network (CAN) Power Mode Zero bus, Body Control Module/Gateway module (BCM/GWM) and FlexRay circuit.

To protect the system from extremes of pressure, the ATCM will disengage the clutch to switch off the A/C compressor if the pressure:

Decreases to 1.9 ± 0.2 bar (27.5 ± 3 lbf/in² ); the ATCM loads the A/C compressor again when the pressure increases to 2.8 ± 0.2 bar (40.5 ± 3 lbf/in2).
Increases to 33 ± 1 bar (479 ± 14.5 lbf/in2); the ATCM loads the A/C compressor again when the pressure decreases to 23.5 ± 1 bar (341 ± 14.5 lbf/in2).