Air Conditioning (A/C) Compressor Torque

The ATCM calculates A/C compressor torque using refrigerant pressure, ambient air temperature and compressor solenoid current. The calculated torque is transmitted on the High Speed (HS) Controller Area Network (CAN) comfort systems bus to the Body Control Module/Gateway Module (BCM/GWM) assembly. The BCM/GWM assembly then transmits the message to the Powertrain Control Module (PCM) on the HS CAN powertrain systems bus.

Under extreme conditions the PCM sends a HS CAN message requesting the ATCM to limit A/C compressor torque. This causes the ATCM to reduce the solenoid current. If the PCM transmits the HS CAN message, the ATCM reduces the A/C solenoid current to zero and then disengages the A/C compressor clutch.