Air Conditioning (A/C) Compressor Control

The ECM controls the operation of the A/C compressor and reacts to requests from the ATC module via the high speed CAN bus. The compressor is a variable displacement unit and the ECM controls, via a solenoid, the displacement of the compressor to adjust load during certain driving conditions.

During engine start-up, moving from a standstill and under hard acceleration, the ECM sets the minimum displacement of the compressor to reduce the effect on the engine torque output. The ECM uses information from the ATC module, the A/C pressure sensor, the electric throttle TP sensor and the ECT sensor to determine compressor control. The ATC module transmits climate control and driver requests to the ECM and the ECM determines the priority of these requests over engine performance.