<p>Is your BL Touch a v3 (likely if you've only just purchased it)? If so, make sure you're using the bugfix version of Marlin 1.1.9, which supposedly fixes the compatibility issues. I say supposedly because there's also a capacitor on the mainboard that can be removed to fix the issue, and once I removed it (and commented out the specific v3 bits in the firmware) the BLTouch performed noticeably better than when relying on the bugfix firmware alone.</p>

<p><a href="https://www.youtube.com/channel/UCbgBDBrwsikmtoLqtpc59Bw" rel="nofollow noreferrer">Teaching Tech on YouTube</a> has a few BLtouch Ender 3 videos, covering the changes for configuring the bugfix firmware and the removal of the capacitor.</p>

CC BY-SA 4.0
2019-06-25T11:24:32.923Z
Oh yeah, I forgot about that. Yes, it is a v3, so the updated firmware should help with the other issues but I still think it also may be a wiring issue because of the inconsistency of failure. I just ordered a replacement so I'll update accordingly once I get the new one set up with the bugfix firmware. Thanks.
Blubberguy22
CC BY-SA 4.0
2019-06-25T14:41:49.880Z
I'd recommend getting ready with the bugfix firmware and the v3 settings it comes with ahead of time so that you can try it with the existing probe and wiring and be 100% sure that this wasn't the cause.
StringsOnFire
CC BY-SA 4.0
2019-07-31T21:51:53.887Z
Good to see you solved the problem and took the time to share it with us! Please post your last edit as a separate answer posting to stick to the Q and A format of SE sites. Please accept your answer (after 48 hours) so that it does not pop up to the top of the queue once in a while. This also will help us in reducing the [unanswered questions list](https://3dprinting.stackexchange.com/unanswered).
0scar
CC BY-SA 4.0
2019-08-01T15:21:03.517Z
I followed the same guides and everything works now. I believe the bugfix firmware is what resolved the issue. Unfortunately I had returned the old probe so I wasn't able to test that but I did try different wires on it and it still failed, so that leads me to believe it was a software issue.
Blubberguy22
CC BY-SA 4.0
2019-06-25T10:50:22.490Z
2019-08-01T21:11:38.437Z
2019-08-01T21:11:38.437Z
StringsOnFire
<p>Just leaving this note here as I have had my own BLTouch issues, maybe it will help someone else...</p>
<p>V4.2.2 board on an Ender 3. BLTouch V3</p>
<p>I was getting inconsistent failures on both home and bed level, also would drive into the bed on occasions.</p>
<p>I would first recommend keeping your Z stop switch connected (the BLTouch uses the five pin header on the V4 boards, not the Z stop.</p>
<p>I tried with extension cable and connectors, then hard wired the extension cable, also removed the pin header plastic body on the connector going into the board (as it's not the right type, and sits a bit too high) to make the cable ensure good connection to V4 board.</p>
<p>Correctly levelled bed, Z stop, was getting awesome prints with stock Creality firmware for Ender 3 Pro and BLTouch on v4.2.2 board (without adaptor board version).</p>
<p>Still random crashes into the bed and random bed level fails.</p>
<p>I'm racking my brains, replaced nearly all wiring, made sure good connections, changed to Marlin 2.X.X bugfix (which you load onto SD and turn the machine on).</p>
<p>Still random crashes into the bed and bed level fails.</p>
<p>So I'm now getting close to, this has to be a faulty touch surely, I've done my fair share of electronics repair being an electronics engineer by trade.</p>
<p>I'm looking at the touch, I see a solonoid, I checked how it works, the ferrite core looks flush with the top of the touch housing. I turn it a full turn into the touch. I'm getting less errors.</p>
<p>I think I finally ended up turning it about 0.5 mm to a 1 mm into the housing. All seems much better. No fails or crashes since the last tweak of the ferrite grub screw.</p>
<p>If the sensor is a little off on the Ender, and I hear they are, then maybe the position of the ferrite is more sensitive on these machines. That will affect the magnetic flux of the sensor.</p>
<p>I also found a link brief on the V3 probes and there is a section that points out a 0.3 mm gap from top of ferrite to top of probe stated, mine was flush.</p>
<p>I have ordered another just to be on the safe side but I think this may have helped stop my random fails.</p>
<hr />
<p>After moving house, pulling printer down and rebuilding, I had this issue again... groan....</p>
<p>This time I found the issue, its firmware.</p>
<p>After going through 2 touch probes, rewired (again), screening touch to ground and more, still doing it.</p>
<p>So I got the latest marlin 2.0.9, compiled it, boom, not a single failure......</p>
<p>lesson learnt</p>

CC BY-SA 4.0
2021-04-12T14:01:34.503Z
I have the same setup as you and I'm encountering the exact same problems.  Leaving the z-stop switch plugged in didn't stop it from driving the nozzle into the print bed.  I'm trying out your suggestion of screwing in the core a bit more, and I also zip-tied the wires to the bltouch in case they were too loose.
Taegost
CC BY-SA 4.0
2020-12-11T17:23:42.057Z
2021-07-07T15:17:21.710Z
2021-07-07T15:17:21.710Z
Paul Smith
<p>I had the same problem. It seems it was definitely a loose connection on the BLTouch.  I put a wire tie around the neck of the BLTouch, just underneath the mounting feet, to secure the wire and ensure a good connection regardless of position. It has worked great so far.</p>

CC BY-SA 4.0
2021-02-23T12:34:07.903Z
2021-02-23T12:34:07.903Z
w1r3d
<p>I found this and remember doing something similar on my TAZ 5 when I installed a proximity sensor on it.  See <a href="https://www.antclabs.com/creality3d-board" rel="nofollow noreferrer">BLTouch V3 on the Creality3D CR-10S Pro</a>:</p>
<blockquote>
<p>Creativity recommends connecting white and black lines to Z+ and
downloading the Creativity firmware.</p>
<p>The BLTouch V3.x is enough just to install the jumper cap on the
CR-10S Pro and it works well in Default(OD) and 5V Logic Mode.
(including Smart V3.0 produced by April 4th, 2019)</p>
<p>This solution is complete and safe. You do not need to remove the
capacity or add a pull-up resistor for the BLTouch installation in the
CR-10S Pro.</p>
<h3>Cause of problem: When the inductive proximity sensor is removed from the Ribbon cable breakout adapter, 24V is kept at EL357N pin1</h3>
<p>(Anode) through R8, so EL357N pin 4(Collector) is fixed LOW.</p>
<h3>Solution: Install the Jumper cap between the Z-connector signal and  GND pin on the Ribbon cable breakout adapter.. It prevent the</h3>
<p>EL357N pin4(Collector) to fix LOW.</p>
<h3>How to install the jumper cap: Remove the inductive proximity sensor from the Ribbon cable breakout adapter for CR-10S PRO and</h3>
<p>install the jumper cap as like the picture. This operation requires
caution.</p>
<p><a href="https://i.sstatic.net/6W2oH.jpg" rel="nofollow noreferrer" title="Board"><img src="https://i.sstatic.net/6W2oH.jpg" alt="Board" title="Board" /></a></p>
<p>※ Never install the Jumper cap between the Z-connector 24V pin and the
GND pin on the Ribbon cable breakout adapter.</p>
<h3>CR-10S Pro Wiring:</h3>
<p><a href="https://i.sstatic.net/0XxDN.jpg" rel="nofollow noreferrer" title="Schematic"><img src="https://i.sstatic.net/0XxDN.jpg" alt="Schematic" title="Schematic" /></a></p>
<p>See Schematic. Using the 5V Logic Mode without the jumper cap
installation may break BLTouch or EL357N.</p>
<p><a href="https://i.sstatic.net/TToao.jpg" rel="nofollow noreferrer" title="Wiring"><img src="https://i.sstatic.net/TToao.jpg" alt="Wiring" title="Wiring" /></a></p>
</blockquote>

CC BY-SA 4.0
2021-05-15T14:46:45.700Z
Hi RoRo and welcome to SE.3DP..! Please include the info from the page in future, otherwise your answer is a link only answer, and these tend to get flagged for deletion. If (or rather, when) the link dies, then your answer won't be as much as as it could have been had the info been included within the answer. I had added the info for you this time. Many thanks.
Greenonline
CC BY-SA 4.0
2021-05-15T12:22:47.773Z
2021-05-15T14:44:07.040Z
2021-05-15T14:44:07.040Z
RoRo
<p>Reviving old thread...</p>
<p>I have same problem on Ender-3 V2 and two BLTouch sensors. So far, Oscar's idea of screwing in the T10 Torx screw on the BLTouch seems to be working. When the torx screw is screwed in you can see the tip of the probe being pushed out a bit. Evidently, there is a magnet in the BLTouch and there is some metal part on the probe that is attracted to the magnet. When the probe gets close enough to the magnet it snaps to the upper (stowed) position. The Torx screw adjusts the position of the magnet. By screwing the Torx in the magnet is closer to the probe and the probe snaps to the magnet sooner.</p>
<p>The BLTouch firmware can detect when the probe has been been snapped up by the magnet. Apparently, the firmware will only probe downward a limited amount. If the probe is not snapped to the magnet by the end of that travel the firmware will abort the probe. My guess is that from the factory the BLTouch is adjusted at the ragged edge of the firmware's detection travel. By screwing it in a bit it the probe stays within the firmware's travel limit.</p>
<p>Since I haven't disassembled either of my BLTouchs this is mostly speculative. Caveat emptor.</p>
<p>BTW, my printer is connected to Octoprint on Android tablet. Disconnecting the Octoprint and USB cable didn't help.</p>

CC BY-SA 4.0
2023-01-07T00:21:27.767Z
2023-01-07T00:21:27.767Z
Chuck
<p>Is it something like in this video?
Extending/retracting when NOT probing works fine, but probing fails with the pin not correctly retracting?</p>
<p><div class="youtube-embed"><div>
                <iframe width="640px" height="395px" src="https://www.youtube.com/embed/AJjYDmRgy1s?start=0"></iframe>
            </div></div></p>
<p>Then the BLtouch is defective and it should be replaced. It is not a firmware issue.</p>

CC BY-SA 4.0
2021-02-24T20:01:46.450Z
2021-02-24T20:01:46.450Z
FarO
<p>I've been through the <a href="/q/6959">same sort of issues</a> and eventually found that it was attributed by the cable and connector. Re-check or re-wire the sensor, this helped me out.</p>

CC BY-SA 4.0
2019-06-25T11:25:08.160Z
I figured as much. I ordered a replacement, so hopefully that resolves the issues.
Blubberguy22
CC BY-SA 4.0
2019-06-23T21:41:15.600Z
2019-06-23T21:41:15.600Z
0scar
<p>I just installed my (v3) BLTouch with a vanilla version of Marlin (1.1.9) on my Ender 3 and everything seems to work fine (including auto home) except the probing. It repeatedly does the first three probes (successfully) but then tries the fourth and fails. Even when disabling the axis movement (X/Y stepper motors) the issue persists, which would indicate that it is not a bad connection or physical location dependent. Any ideas on how to troubleshoot?</p>
<p>On second thoughts, it seems that it now fails inconsistently, so it is probably a wiring issue, although there is still the issue of it not retracting before printing and not leveling well when it does (although those issues would be more appropriate for a separate question), among other things.</p>
<p>&lt;Edit: Resolved, I both replaced the BLTouch and updated my firmware, but I believe it was the latter that fixed it.&gt;</p>

CC BY-SA 4.0
2019-06-24T06:11:26.127Z
This is a loose wire, may be some strength is pulling the wire while moving from XX,XY,YY then you get the failure. Also happens with the temperature sensor or even the heat resistor. Keep your wires tightened to connectors.
Fernando Baltazar
CC BY-SA 4.0
2019-06-25T11:26:33.427Z
It also fails when disabling the X and Y motors, so I'm not sure if it's a pulling as much as a poor connection.
Blubberguy22
CC BY-SA 4.0
2020-12-16T00:13:13.800Z
Thanks for posting your solution, I have a brand new V3, and when through all of the cable testing, etc. I turned my grub screw 1/4 turn into the housing, and its working consistently now. I thought I was going to have to return for refund/exchange. I think I will order a backup just in case.
dminkler
<marlin><bed-leveling><bltouch>
BLTouch Probing Fails Intermittently
Blubberguy22
# BLTouch Probing Fails Intermittently

(Asked by: username_0 on 2019-06-22)

I just installed my (v3) BLTouch with a vanilla version of Marlin (1.1.9) on my Ender 3 and everything seems to work fine (including auto home) except the probing. It repeatedly does the first three probes (successfully) but then tries the fourth and fails. Even when disabling the axis movement (X/Y stepper motors) the issue persists, which would indicate that it is not a bad connection or physical location dependent. Any ideas on how to troubleshoot?

On second thoughts, it seems that it now fails inconsistently, so it is probably a wiring issue, although there is still the issue of it not retracting before printing and not leveling well when it does (although those issues would be more appropriate for a separate question), among other things.

**Tags:** marlin, bed-leveling, bltouch
> **Comments:**
> **username_1**: This is a loose wire, may be some strength is pulling the wire while moving from XX,XY,YY then you get the failure. Also happens with the temperature sensor or even the heat resistor. Keep your wires tightened to connectors.  
> **username_0**: It also fails when disabling the X and Y motors, so I'm not sure if it's a pulling as much as a poor connection.  
> **username_2**: Thanks for posting your solution, I have a brand new V3, and when through all of the cable testing, etc. I turned my grub screw 1/4 turn into the housing, and its working consistently now. I thought I was going to have to return for refund/exchange. I think I will order a backup just in case.  

---

## 7 answers

### Answer by username_3 on 2019-06-25. Score: 4 | Accepted answer

Is your BL Touch a v3 (likely if you've only just purchased it)? If so, make sure you're using the bugfix version of Marlin 1.1.9, which supposedly fixes the compatibility issues. I say supposedly because there's also a capacitor on the mainboard that can be removed to fix the issue, and once I removed it (and commented out the specific v3 bits in the firmware) the BLTouch performed noticeably better than when relying on the bugfix firmware alone.

[Teaching Tech on YouTube](https://www.youtube.com/channel/UCbgBDBrwsikmtoLqtpc59Bw) has a few BLtouch Ender 3 videos, covering the changes for configuring the bugfix firmware and the removal of the capacitor.

> **Comments:**
> **username_0**: Oh yeah, I forgot about that. Yes, it is a v3, so the updated firmware should help with the other issues but I still think it also may be a wiring issue because of the inconsistency of failure. I just ordered a replacement so I'll update accordingly once I get the new one set up with the bugfix firmware. Thanks.  
> **username_3**: I'd recommend getting ready with the bugfix firmware and the v3 settings it comes with ahead of time so that you can try it with the existing probe and wiring and be 100% sure that this wasn't the cause.  
> **username_4**: Good to see you solved the problem and took the time to share it with us! Please post your last edit as a separate answer posting to stick to the Q and A format of SE sites. Please accept your answer (after 48 hours) so that it does not pop up to the top of the queue once in a while. This also will help us in reducing the [unanswered questions list](https://3dprinting.stackexchange.com/unanswered).  
> **username_0**: I followed the same guides and everything works now. I believe the bugfix firmware is what resolved the issue. Unfortunately I had returned the old probe so I wasn't able to test that but I did try different wires on it and it still failed, so that leads me to believe it was a software issue.  

---

### Answer by username_5 on 2020-12-11. Score: 1

Just leaving this note here as I have had my own BLTouch issues, maybe it will help someone else...

V4.2.2 board on an Ender 3. BLTouch V3

I was getting inconsistent failures on both home and bed level, also would drive into the bed on occasions.

I would first recommend keeping your Z stop switch connected (the BLTouch uses the five pin header on the V4 boards, not the Z stop.

I tried with extension cable and connectors, then hard wired the extension cable, also removed the pin header plastic body on the connector going into the board (as it's not the right type, and sits a bit too high) to make the cable ensure good connection to V4 board.

Correctly levelled bed, Z stop, was getting awesome prints with stock Creality firmware for Ender 3 Pro and BLTouch on v4.2.2 board (without adaptor board version).

Still random crashes into the bed and random bed level fails.

I'm racking my brains, replaced nearly all wiring, made sure good connections, changed to Marlin 2.X.X bugfix (which you load onto SD and turn the machine on).

Still random crashes into the bed and bed level fails.

So I'm now getting close to, this has to be a faulty touch surely, I've done my fair share of electronics repair being an electronics engineer by trade.

I'm looking at the touch, I see a solonoid, I checked how it works, the ferrite core looks flush with the top of the touch housing. I turn it a full turn into the touch. I'm getting less errors.

I think I finally ended up turning it about 0.5 mm to a 1 mm into the housing. All seems much better. No fails or crashes since the last tweak of the ferrite grub screw.

If the sensor is a little off on the Ender, and I hear they are, then maybe the position of the ferrite is more sensitive on these machines. That will affect the magnetic flux of the sensor.

I also found a link brief on the V3 probes and there is a section that points out a 0.3 mm gap from top of ferrite to top of probe stated, mine was flush.

I have ordered another just to be on the safe side but I think this may have helped stop my random fails.

---

After moving house, pulling printer down and rebuilding, I had this issue again... groan....

This time I found the issue, its firmware.

After going through 2 touch probes, rewired (again), screening touch to ground and more, still doing it.

So I got the latest marlin 2.0.9, compiled it, boom, not a single failure......

lesson learnt

> **Comments:**
> **username_6**: I have the same setup as you and I'm encountering the exact same problems.  Leaving the z-stop switch plugged in didn't stop it from driving the nozzle into the print bed.  I'm trying out your suggestion of screwing in the core a bit more, and I also zip-tied the wires to the bltouch in case they were too loose.  

---

### Answer by username_7 on 2021-02-23. Score: 1

I had the same problem. It seems it was definitely a loose connection on the BLTouch. I put a wire tie around the neck of the BLTouch, just underneath the mounting feet, to secure the wire and ensure a good connection regardless of position. It has worked great so far.


---

### Answer by username_8 on 2021-05-15. Score: 1

I found this and remember doing something similar on my TAZ 5 when I installed a proximity sensor on it. See [BLTouch V3 on the Creality3D CR-10S Pro](https://www.antclabs.com/creality3d-board):

> Creativity recommends connecting white and black lines to Z+ and
> downloading the Creativity firmware.
>
> The BLTouch V3.x is enough just to install the jumper cap on the
> CR-10S Pro and it works well in Default(OD) and 5V Logic Mode.
> (including Smart V3.0 produced by April 4th, 2019)
>
> This solution is complete and safe. You do not need to remove the
> capacity or add a pull-up resistor for the BLTouch installation in the
> CR-10S Pro.
>
> ### Cause of problem: When the inductive proximity sensor is removed from the Ribbon cable breakout adapter, 24V is kept at EL357N pin1
>
> (Anode) through R8, so EL357N pin 4(Collector) is fixed LOW.
>
> ### Solution: Install the Jumper cap between the Z-connector signal and GND pin on the Ribbon cable breakout adapter.. It prevent the
>
> EL357N pin4(Collector) to fix LOW.
>
> ### How to install the jumper cap: Remove the inductive proximity sensor from the Ribbon cable breakout adapter for CR-10S PRO and
>
> install the jumper cap as like the picture. This operation requires
> caution.
>
> [![Board](https://i.sstatic.net/6W2oH.jpg "Board")](https://i.sstatic.net/6W2oH.jpg "Board")
>
> ※ Never install the Jumper cap between the Z-connector 24V pin and the
> GND pin on the Ribbon cable breakout adapter.
>
> ### CR-10S Pro Wiring:
>
> [![Schematic](https://i.sstatic.net/0XxDN.jpg "Schematic")](https://i.sstatic.net/0XxDN.jpg "Schematic")
>
> See Schematic. Using the 5V Logic Mode without the jumper cap
> installation may break BLTouch or EL357N.
>
> [![Wiring](https://i.sstatic.net/TToao.jpg "Wiring")](https://i.sstatic.net/TToao.jpg "Wiring")

> **Comments:**
> **username_9**: Hi RoRo and welcome to SE.3DP..! Please include the info from the page in future, otherwise your answer is a link only answer, and these tend to get flagged for deletion. If (or rather, when) the link dies, then your answer won't be as much as as it could have been had the info been included within the answer. I had added the info for you this time. Many thanks.  

---

### Answer by username_10 on 2023-01-07. Score: 0

Reviving old thread...

I have same problem on Ender-3 V2 and two BLTouch sensors. So far, Oscar's idea of screwing in the T10 Torx screw on the BLTouch seems to be working. When the torx screw is screwed in you can see the tip of the probe being pushed out a bit. Evidently, there is a magnet in the BLTouch and there is some metal part on the probe that is attracted to the magnet. When the probe gets close enough to the magnet it snaps to the upper (stowed) position. The Torx screw adjusts the position of the magnet. By screwing the Torx in the magnet is closer to the probe and the probe snaps to the magnet sooner.

The BLTouch firmware can detect when the probe has been been snapped up by the magnet. Apparently, the firmware will only probe downward a limited amount. If the probe is not snapped to the magnet by the end of that travel the firmware will abort the probe. My guess is that from the factory the BLTouch is adjusted at the ragged edge of the firmware's detection travel. By screwing it in a bit it the probe stays within the firmware's travel limit.

Since I haven't disassembled either of my BLTouchs this is mostly speculative. Caveat emptor.

BTW, my printer is connected to Octoprint on Android tablet. Disconnecting the Octoprint and USB cable didn't help.


---

### Answer by username_11 on 2021-02-24. Score: 0

Is it something like in this video?
Extending/retracting when NOT probing works fine, but probing fails with the pin not correctly retracting?

Then the BLtouch is defective and it should be replaced. It is not a firmware issue.


---

### Answer by username_4 on 2019-06-23. Score: 0

I've been through the [same sort of issues](/q/6959) and eventually found that it was attributed by the cable and connector. Re-check or re-wire the sensor, this helped me out.

> **Comments:**
> **username_0**: I figured as much. I ordered a replacement, so hopefully that resolves the issues.  

---

