Circuit Description

A/C refrigerant pressure sensor is located on high side of A/C system and is used to monitor refrigerant pressure. PCM uses this information to run cooling fans when A/C refrigerant pressure is high. A 5-volt reference voltage is supplied to sensor and is returned to PCM on signal circuit. Sensor resistance changes as refrigerant pressure increases or decreases.

PCM monitors A/C refrigerant pressure sensor signal circuit and can determine when A/C pressure is too high or too low. When pressures are out of range (high or low) for a predetermined time, PCM will disable A/C compressor clutch and set DTC.

DTC will set when the following conditions are present:

• A/C refrigerant pressure sensor indicates A/C refrigerant pressure is less than 3 psi for 5 seconds.
• A/C refrigerant pressure sensor indicates A/C refrigerant pressure is greater than 445 psi for 5 seconds.