Do the following:

Switch on printer
Auto Home

• it should now be in the middle of the bed about an inch up.
  Now go to MOVE and select Move Z axis
  The Z Axis value will be something like 10 or 13
  Change the value to 0.0 and the head will lower a bit.
  Now get a piece of paper and put under the nozzle.
  Go to PREPARE > Z OFFSET
  Change this to about 2.00
  The head should lower further.
  Keep adjusting it in 0.05 increments until you can just move the paper.
  It should now be adjusted correctly.
  Finally go back to the main screen and select LEVEL.

See how you go.

@Pico @Jwnok

Hi,

I've just spent three days trying to get the BLTouch v3.1 working with my Ender 3 v2 4.2.2 board. I had exactly the same issue with both crashing into the bed and random intermittent flashing red failures.

This morning, purely by accident I refitted the BLTouch sensor with the connector and PCB to the left, rather than facing the hot end. Not a single issue since.

I read that the hot end can create interference with the signal, and so maybe having the pcb etc further away has helped.

I'm using the stock Creality BLTouch enabled firmware (4.1.1). Gave up trying to get TH3D or other custom Marlin firmware code to work.

I am using the following scripts in Cura for Start and End G-Code:

; Ender 3 V2 Custom Start G-code
M140 S{material_bed_temperature_layer_0} ; Set Heat Bed temperature
M190 S{material_bed_temperature_layer_0} ; Wait for Heat Bed temperature
M104 S150; start warming extruder to 150
G28                         ; Home all axes
G29 ; BLTouch ABL
G92 E0                      ; Reset Extruder
M104 S{material_print_temperature_layer_0} ; Set Extruder temperature
G1 Z2.0 F1200               ; Move Z Axis up little to prevent scratching of Build Plate
M109 S{material_print_temperature_layer_0} ; Wait for Extruder temperature
G1 X0 Y20 Z0.3 F9000        ; Move to start position
G1 X0 Y200 Z0.3 F1200 E15   ; Draw the first line
G1 X0.4 Y200 Z0.3 F9000     ; Move to side a little
G1 X0.4 Y20 Z0.3 F1200 E30  ; Draw the second line
G92 E0                      ; Reset Extruder
G1 X0 Y10 Z0.2              ; Wipe Nozzle
G1 Z2                       ; Move Z Axis up little to prevent scratching of Build Plate

And the End Code....

; Ender 3 V2 Custom End G-code
G90                         ; Set Absolute positioning
G92 E0                      ; Reset the extruder position
G0 E-3                      ; Retract filament
G0 X0 Y{machine_depth} Z{machine_height} F9000 ; Present the print, build plate to the front, Z at the top
M106 S0                     ; Turn-off cooling fan
M104 S0                     ; Turn-off hotend
M140 S0                     ; Turn-off bed
M84                         ; Disable all steppers
M300 S2000 P200             ; Make Ending Sound 3 beeps
M300 S0 P100
M300 S2000 P200
M300 S0 P100
M300 S2000 P200