A/C Refrigerant Pressure Sensor

The A/C pressure sensor signal indicates high side refrigerant pressure to the PCM. The PCM uses this information to adjust the Idle Air Control (IAC) valve in order to compensate for the higher engine loads present with high A/C refrigerant pressures and to control the cooling fans. The PCM also shares the A/C pressure sensor information with the HVAC controller. The HVAC controller uses the information to decide whether or not to send the A/C request signal to the PCM. If a fault occurs in the A/C pressure sensor circuit, the HVAC controller removes the request for A/C and the PCM disables the A/C relay.