A/C Pressure Sensor: Notes

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

A/C SENSOR OUTPUT VOLTAGE SPECIFICATION

A/C System Pressure⁽¹⁾

Sensor Output Voltage (V out)

System Operation

HDS PGM-FI Data List

Abnormally low pressure: Below 196 kPa (2.00 kgf/cm² , 28.4 psi)

Below 0.685 V

The ECM/PCM disengages the compressor clutch. The radiator and A/C condenser fans operate based on engine coolant temperature.

FAN HIGH CONTROL: ON, OFF
FAN LOW CONTROL: ON, OFF
A/C PRESSURE SENSOR: V, kPa (kgf/cm² )

Normal operating pressure:

Above 196 kPa (2.00 kgf/cm² , 28.4 psi)
Below 1, 230 kPa (12.54 kgf/cm² , 178.4 psi)

0.686 V to 1.944 V

The ECM/PCM cycles the compressor clutch based on cooling demand. The radiator and A/C condenser fans operate at low speed unless the engine coolant temperature exceeds 206°F (97°C).

High operating pressure:

Above 1, 230 kPa (12.54 kgf/cm² , 178.4 psi)
Below 3, 138 kPa (32.00 kgf/cm² , 455.1 psi)

1.945 V to 4.575 V

The ECM/PCM cycles the compressor clutch based on cooling demand. The radiator and 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 ECM/PCM disengages the compressor clutch. The radiator and A/C condenser fans operate based on engine coolant temperature.

⁽¹⁾	The A/C system pressure can be monitored in the HDS PGM-FI Data List

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

Fig 1: A/C Pressure Sensor Ouptput Voltage Graph

Courtesy of AMERICAN HONDA MOTOR CO., INC.