This has been covered exhaustively in other threads.
The HW in the car was never designed or intended for this task and is simply not capable of doing this job in any useful or reliable way. Low quality camera, in the wrong place, at the wrong angle, with no interior lighting of any kind to support its use for this purpose.
Look at what Caddy did to make this happen- much more advanced camera- in a totally different location/angle- and with IR to handle lighting conditions. And even THEN it doesn't work 100% of the time (has some issues with really bright sunlight in some conditions)