Refrigerant Pressure Sensor

Fig 1: Refrigerant Pressure Sensor

Courtesy of JAGUAR CARS, INC.

The refrigerant pressure sensor provides the automatic temperature control (ATC) module with a pressure input from the high pressure side of the refrigerant system. The refrigerant pressure sensor is located in the refrigerant line between the condenser and the thermostatic expansion valve.

The automatic temperature control (ATC) module supplies a 5 V reference voltage to the refrigerant pressure sensor and receives a return signal voltage, between 0 V and 5 V, related to system pressure.

The automatic temperature control (ATC) module uses the signal from the pressure sensor to protect the refrigerant system from extremes of pressure. The automatic temperature control (ATC) module transmits the air conditioning (A/C) pressure, along with the compressor drive current value, to the instrument cluster on the medium speed controller area network (CAN) bus. These signals are broadcast to the engine control module (ECM) on the high speed controller area network (CAN) bus to allow it to calculate the torque being applied to the engine by the compressor.

To protect the system from extremes of pressure, the automatic temperature control (ATC) module sets the air conditioning (A/C) compressor to the minimum flow position if the pressure:

• Decreases to 2.1 ± 0.2 bar (31.5 ± 3 lbf/in² ); the automatic temperature control (ATC) module loads the air conditioning (A/C) compressor again when the pressure increases to 2.3 ± 0.2 bar (33.4 ± 3 lbf/in² )
• Increases to 31 ± 1 bar (450 ± 14.5 lbf/in² ); the automatic temperature control (ATC) module loads the air conditioning (A/C) compressor again when the pressure decreases to 26 ± 1 bar (377 ± 14.5 lbf/in² )