Ender 3 v2 v4.2.2 - Bltouch - STOP called because of BLTouch error - restart with M999

I’ve just fitted a new BL touch to my Ender 3 v2 and installed the following firmware.

When I start a print it will occationally stop with a bltouch error and octoprint disconnects from the serial. The printer will then sit there with the bltouch flashing red and I am unable to reconnect to the serial. I have to power down the printer and try the print again.

The bltouch was purchased from the creality store on Ali Express.

Is there anything I can try before throwing the bltouch in the bin?


Normally this means that the BLTouch doesn’t seem to be behaving.

Have you checked the wiring according to the FAQ?

As a rule of thumb, if the probe is deploying, but then errors, the problem is with the black/white wires.

If the probe never deploys, the problem is with the group of 3 wires that carry the control signals and power to the BLTouch (or compatible) probe.

The version I have has a cable with a single connector at each end (v3 smart?) and it’s impossible to plug-in incorrectly. I will check the cabling and test for continuity, I guess something could be loose.

I just found this page suggesting PWM values might need to be tweaked in the firmware?

This hasn’t been a problem for a long time - the BLTouch specific FAQ is rather old and hasn’t been updated in a VERY long time. It’s on my todo list along with many more items :laughing:

The key part is if the probe deploys or not.

It’s a bit hit and miss, if the self-test works (2x depploy / retract) then the bed leveling seems to go ahead without problem. Some times is works and prints fine, other times it fails on startup.

Ok, if the probe fails its deployment - ie the pin doesn’t pop out, put a hex key in the slug on the top of the BLTouch and rotate it 180 degrees clockwise (as looking down onto the top of the BLTouch). Don’t go past 180 degrees - as this is quite sensitive.


Make sure you use a correct fitting hex key - as the slug is quite fragile.

Then, try your testing again.

Thanks for your help, I tried adjusting the screw but it didn’t make any difference. I’ve now replaced the bltouch and it appears to work much more reliably.

Always the way - at least its sorted now.