APT Sensor
WARNING: This page is about a different car, the 2021 Hyundai Kona. However, it is still accessible from the selected car via links, so may be relevant.
The A/C Control Module receives the A/C Pressure Transducer (APT) Sensor input from the PCM (engine ECM) through CAN lines and computes the A/C coolant pressure. If the pressure reading is abnormal, the A/C Control Module will shut off the A/C compressor until the pressure is within the normal range.