I experienced a code 4 issue after having previously initializing and using the Pro over various projects before with no issues. After frustrating hours of on/off switching and re-initializing the system with no apparent success to get the bit to drop down to the bit setter, I finally discovered my problem.
I had accidentally allowed the magnetic button for the Bit Zero Probe V2 to come into contact with the Probe base, thereby establishing a constant ground back to the system which effectively disabled the initialization process.
Once the magnet and the probe base was separated, the system initialized and the probe setting procedure successfully accomplished … the system now appears to be functioning normally.