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A/C Pressure Sensor

The A/C pressure sensor converts A/C pressure into electrical signals to the PCM.

A/C System Pressure Sensor Output Voltage (V out) System Operation
Abnormally low pressure: Below 196 kPa (2.00 kgf/cm2 , 28.4 psi) Below 0.685 V The PCM disengages the A/C compressor clutch. The radiator and the A/C condenser fans operate based on engine coolant temperature.
Normal operating pressure:
  • Above 196 kPa (2.00 kgf/cm2 , 28.4 psi)
  • Below 1, 470 kPa (14.99 kgf/cm2 , 213.2 psi)
0.686 V to 1.944 V The PCM cycles the A/C compressor clutch based on cooling demand. The radiator and the A/C condenser fans operate at low speed unless the engine coolant temperature exceeds 206°F (97°C).
High operating pressure:
  • Above 1, 470 kPa (14.99 kgf/cm2 , 213.2 psi)
  • Below 3, 138 kPa (32.00 kgf/cm2 , 455.1 psi)
1.945 V to 4.575 V The PCM cycles the A/C compressor clutch based on cooling demand. The radiator and the A/C condenser fans operate at high speed.
Abnormally high pressure: More than 3, 138 kPa (32.00 kgf/cm2 , 455.1 psi) Above 4.575 V The PCM disengages the A/C compressor clutch. The radiator and the A/C condenser fans operate based on engine coolant temperature.
*: The A/C system high side pressure can be monitored through the climate control sensor input display function (see RUN THE SENSOR INPUT DISPLAY MODE  ).

The response of the A/C pressure sensor is shown in the graph.

NOTE: When the refrigerant is below 196 kPa (2.00 kgf/cm2 , 28.4 psi) or above 3, 138 kPa (32.00 kgf/cm2 , 455.1 psi), the PCM turns the A/C compressor clutch relay off to protect the A/C compressor. When the refrigerant pressure is above 1, 470 kPa (14.99 kgf/cm2 , 213.2 psi), the PCM switches the radiator and the A/C condenser fans to high speed.
Fig 1: A/C Pressure Sensor Graph
G08076186Courtesy of AMERICAN HONDA MOTOR CO., INC.