A/C Refrigerant Pressure Sensor

The electronic A/C refrigerant pressure sensor is mounted to the line between the condenser and the evaporator. The output to the PCM is variable and depends on the pressure inside the line. A higher pressure will result in a higher voltage out.

The PCM constantly monitors the A/C system pressure in order to achieve the following effects:
^ Disengage the A/C clutch it the pressure is above 2700 kPa (440 psi).
^ Disengage the A/C clutch if pressure is below 285 kPa (38 psi).
^ Boost the idle air control in order to compensate for the A/C load at idle.
^ Control the cooling fan operation.

A fault in the A/C refrigerant pressure sensor signal will cause DTC P0530 to set.

The A/C Compressor Control Circuit Diagnosis should be used for diagnosing the electrical portion of the A/C compressor clutch circuit. When diagnosing the refrigerant portion of the HVAC system, the Cooling Insufficient, A/C System in HVAC should be used.

A scan tool will be used in diagnosing the system. The scan tool has the ability to read the A/C request and refrigerant pressure inputs to the PCM. The scan tool can display when the PCM has commanded the A/C clutch on. The scan tool should have the ability to override the A/C request signal and energize the A/C control relay.