[amidgeha]

A/C Request (A) Circuit

The Powertrain Control Module (PCM) monitors the refrigerant pressure through the Air Condition (A/C) Pressure Sensor. The PCM supplies a 5V reference and a low reference to the sensor. Changes in the A/C refrigerant pressure causes the sensor signal to the PCM to vary. When the pressure is high, the signal is high. When the pressure is low, the signal is low. The PCM sets the OBII code when the signal from the sensor is out of factory specifications.

Cause:
Low refrigerant
Too much refrigerant
Faulty Low Side Pressure Sensor
Low Side Pressure Sensor harness is open or shorted
Low Side Pressure Sensor circuit poor electrical connection

Symptoms:
Check engine light