Your phone’s sensors drift over time due to temperature changes, drops, or aging. com.sec.facatfunction periodically runs background calibration routines to ensure:
The "sec" in the name stands for Samsung Electronics Co., and "facat" likely refers to "Factory Automation Control and Test" or a similar diagnostic toolset used during manufacturing or hardware repair. Android Internals: A Confectioner's Cookbook Key Details System Role com.sec.facatfunction
When you send your phone to an authorized Samsung service center, technicians use proprietary software that communicates with com.sec.facatfunction to re-calibrate sensors after a screen replacement or motherboard repair. Your phone’s sensors drift over time due to
Every time you look at your phone to unlock it, this service initializes. this service initializes.