<p>After setting up the BLTouch in firmware, you need to activate the leveling function for every print by inserting the leveling G-code <a href="https://reprap.org/wiki/G-code#G29:_Detailed_Z-Probe" rel="nofollow noreferrer">'G29'</a> in the start G-code script of your slicer. The code should be placed directly after command <code>G28</code>.</p>
<p>Note that you can test the working of the sensor from the printer display: sensor can be deployed, stowed, reset and tested.</p>
<p>An alternative is to use the <code>G29</code> and <code>M500</code> command once in a while (for beds that don't change, don't get handled by excessive force and/or are operated at the same temperature) or store the shape of the bed through the display interface and put the command <a href="https://reprap.org/wiki/G-code#M420:_Leveling_On.2FOff.2FFade_.28Marlin.29" rel="nofollow noreferrer"><code>M420 S1</code></a> in your start G-code instead.</p>

CC BY-SA 4.0
2020-06-13T05:24:40.610Z
2021-06-21T14:00:31.280Z
2021-06-21T14:00:31.280Z
0scar
<p>I installed TH3D to my stock mainboard via <a href="https://www.youtube.com/watch?v=3TTuisjmbmY&amp;list=WL&amp;index=47&amp;t=0s" rel="nofollow noreferrer">this guide</a>, but BLTouch does not work properly. </p>

<p>It does not check all 9 points before point it just go middle then check z then start printing. BLTouch normally needs to check all 9 points before printing or with autobedleveling but somehow mine do not work like this.</p>

CC BY-SA 4.0
2020-06-12T22:31:19.373Z
Hi, welcome to 3DPrinting.SE! Did you insert `G29` in your start G-code script?
0scar
CC BY-SA 4.0
2020-06-12T23:30:50.903Z
Hey, yes after a while I understand it and find a gcode that is suitable for ender 3 and bltouch now it seems working fine. Ty for your respond :)
Burak0015
<creality-ender-3><bltouch><th3d>
BLTouch with TH3D Ender 3 pro
Burak0015
# BLTouch with TH3D Ender 3 pro

(Asked by: username_0 on 2020-06-12)

I installed TH3D to my stock mainboard via [this guide](https://www.youtube.com/watch?v=3TTuisjmbmY&list=WL&index=47&t=0s), but BLTouch does not work properly.

It does not check all 9 points before point it just go middle then check z then start printing. BLTouch normally needs to check all 9 points before printing or with autobedleveling but somehow mine do not work like this.

**Tags:** creality-ender-3, bltouch, th3d
> **Comments:**
> **username_1**: Hi, welcome to 3DPrinting.SE! Did you insert `G29` in your start G-code script?  
> **username_0**: Hey, yes after a while I understand it and find a gcode that is suitable for ender 3 and bltouch now it seems working fine. Ty for your respond :)  

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## 1 answers

### Answer by username_1 on 2020-06-13. Score: 2 | Accepted answer

After setting up the BLTouch in firmware, you need to activate the leveling function for every print by inserting the leveling G-code ['G29'](https://reprap.org/wiki/G-code#G29:_Detailed_Z-Probe) in the start G-code script of your slicer. The code should be placed directly after command `G28`.

Note that you can test the working of the sensor from the printer display: sensor can be deployed, stowed, reset and tested.

An alternative is to use the `G29` and `M500` command once in a while (for beds that don't change, don't get handled by excessive force and/or are operated at the same temperature) or store the shape of the bed through the display interface and put the command [`M420 S1`](https://reprap.org/wiki/G-code#M420:_Leveling_On.2FOff.2FFade_.28Marlin.29) in your start G-code instead.


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