BL Touch Error Out of Box

  • On my 3rd Ender 5, first damaged by UPS then the 2nd lost by UPS. Was happy to unbox and setup; however, at startup the BL Touch sensor is in error state and flashing red so it will not home in Z Axis. Will try going down to 1.70.1 version of firmware. Have sent Creality an email but according to some posts it takes a while. All wiring is proper and I can manually move the Z up and down. Took the sensor off and it is connected properly on sensor and all wires match at connector. I have a feeling this one will go back as well.

  • @lwsmiser I beg to differ. Although checking connections and ensuring nothing like foam from the box the BLTouch was packaged in etc is jamming it up, should be your first port of call as you correctly state.

    Flashing red light means failure, and failing to deploy probe is one of them. In my experience the most common cause (dont use pritt stick on your bed, just asking for trouble 🙂 seriously the probe does stick to pritt stick nicely, unlike just about anything else.

    It is fairly common for a new BLTouch to need adjusting for reliable operation even after all cables dodgy connections have been elliminated. This is also stated by Antclabs and full instructions for adjustment including initial 0-~.3 mm (note the ~) installation depth are available on their official website

    The adjustment screw, when re-installed after any maintenance should be set somewhere between 0 and .3mm in depth, then if operation is unreliable adjust clockwise up to 180 degrees, as instructed in the user manual on antclabs website, small-ish amounts maybe only 30 or 40 degrees at a time, up to max 180 degrees will do it. As correctly stated already by @lwsmiser the adjustment is not critical as it does have a fair range of reliable operation. if no improvment is seen in the operation of the power on self test, by 180 degrees, it is not the problem. 100% reliability is easy to acheive and does not require lots of tiny adjustments

    Removing the screw is required so you can remove the pin for inspection/cleaning or replacement. It is a simple matter and in no way to be thought of as anything other than easy, straight forward and a fairly normal activity due to the amount of filament dust etc the BLTouch is likely to be exposed to. After much use, if reliability becomes a problem, the BLTouch is much more likely to require cleaning or tip replacement than adjustment, but you are going to remove the screw to do those things anyway.

    Be gentle with the pin and keep greasy fingers off it.

    Once adjusted it is unlikely to ever need adjusting again but really does not matter due to being so easy to do and the fact most any other remedial action other than cables/connections will require it's removal regardless.

    On another note, ignore anything you read about it setting the strike point or height or raisng the Z or sensitivity etc. It does nothing of the sort and most certainly is not what it is there for.

  • Flashing red usually means a wiring error. Either the probe is not correctly plugged into the main board or one of the connections is not making proper contact. This is usually the black and white wire. White is + and Black is ground. It should plug into the Z stop position replacing the Z end stop switch. However, there are some setups which use a different pin for the Z stop emulation.
    Yes, it is possible too that the probe is bent slightly and cannot deploy and retract properly. So the question is did the probe deploy and retract twice during the startup of the printer? If it did the problem indicated by the blinking red led is a wiring problem. Please don't go about trying to adjust the grub screw in the BLTouch. That is seldom a problem but it should be flush to 0.3mm into the body of the probe. This is not super critical.

  • @slowJEEP maybe you need to adjust the screw on top of the bl touch.

  • Back from the dead but in case someone else has the problem. My BL sensor came stuck in the up position. I had to pull it out manually for it to function correctly. Still getting stuck often but it works when it isn't stuck. Flashing red BL probe is an indicator that the tip is stuck up, for me.

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