Front A/C Pressure Transducer - Operation

OPERATION

The A/C pressure transducer monitors the pressures in the high side of the A/C refrigerant system through its connection to a fitting on the A/C discharge line, and its internal resistance changes in response to the pressures it monitors. The Powertrain Control Module (PCM) provides a five volt reference signal and a sensor ground to the A/C pressure transducer, then monitors the output voltage of the transducer on a sensor return circuit to determine refrigerant pressure. The PCM is programmed to respond to this and other sensor inputs by controlling the operation of the A/C clutch and the radiator cooling fan to help optimize A/C system performance and to protect the A/C system components from damage. The PCM will disengage the A/C clutch when high side pressure rises above 3219 kPa (476 psi) and re-engage the clutch when high side pressure drops below 2937 kPa (426 psi). The A/C pressure transducer will also disengage the A/C clutch if the high side pressure drops below 110 kPa (16 psi) and will re-engage the clutch when the high side pressure rises above 220 kPa (32 psi). When the refrigerant pressure rises above 1655 kPa (240 psi), the PCM will actuate the cooling fan. The A/C pressure transducer signal to the PCM also prevents the A/C clutch from engaging when ambient temperatures are below about 10° C (50° F), due to the pressure/temperature relationship of the refrigerant.

A Schrader-type valve in the A/C discharge line fitting permits the A/C pressure transducer to be removed or installed without disturbing the refrigerant in the A/C system.

The A/C pressure transducer is diagnosed using a scan tool Testing and Inspection.

The A/C pressure transducer cannot be adjusted or repaired and must be replaced if inoperative or damaged.