Creality Ender 3 Pro + CR Touch
If your newly purchased Creality Ender CR Touch auto bed leveling sensor is not working with your Creality Ender-3 Pro 3D printer - you're in the right place. Mine did not work out of the box as well.
The issue
During Z-axis homing, the printing head with the sensor was moving upward a bit instead of downward to the bed surface, then the printer was stopping the probing process with an error. Customer support did not help.
In fact, during the writing of this article, this sensor is marked as a frequently returned item on Amazon. Most likely due to lack of support from sellers and the manufacturer.
The solution
I spent some time digging Marlin source code and the configuration files, and found the root cause of the issue: the sensor falsely triggered due to noise.
This issue can be fixed in the firmware by enabling the endstop noise threshold parameter in the Configuration.h file.
#define ENDSTOP_NOISE_THRESHOLD 3Download
Feel free to build your own Marlin firmware with the corresponding Configuration files or download mine here.
Creality Ender-3 Pro, board v4.2.2, CR Touch sensor