# Homing

## Won't Complete: Just Keeps Skipping

### Problem

I starting homing. The printer starts moving and then it just keeps skipping. It never homes.

### Solution

#### **Your limit switch may not work.**

Let's see if your limit switches works.

Run:

```
M18 X Y; This disables the CoreXY (motion) motors
```

Slowly move the extruder head to the center

Run: 

```
M564 H0; Let's you move the motors without homing.
G91;
```

Manually engage (press down) on the X, Y, and Z Limit Switch. We recommend using tape.

{% hint style="warning" %}
We discourage using your fingers. Do so at your own risk. 
{% endhint %}

Run:

```
G1 Y100 S1;
G1 X100 S1;
G1 Z100 S1;
```

#### Let's evaluate:

If the ***extruder moves forward or backward,*** 

* The Y Limit Switch is not working.

If the ***extruder moves to either side***, 

* The X Limit Switch is not working.

If the ***bed moves down***,

* The Z Limit Switch is not working. 

## Homing Z: Weird Z Endstop Values

### Problem

I am calibrating my z endstop value. After I home Z, the Z endstop value is not what I put.

### Solution

#### Your new z endstop value may not be saved.

Let's check what your current Z Endstop Value is.

Go to ***Settings***. Then click the ***System Editor*** tab. Open the ***machine\_zendstop.g*** file. 

Scroll down to the last line.

Check your Z Endstop Value. Is this the calibrated value?

{% tabs %}
{% tab title="YES" %}
Change it to a new value.

Click "Save Changes" button.

Home the Z.

Check to see if your Z Endstop Value is correct.

If not, continue reading.
{% endtab %}

{% tab title="NO" %}
Continue reading. 
{% endtab %}
{% endtabs %}

#### Your machine boundaries may be too low.

Let's check if your machine boundaries are interfering. 

Go to ***Settings***. Then click the ***System Editor*** tab. Open the ***machine\_axisdimension.g*** file. 

Look for the line labeled " Maximum"

```
M203 X# Y# Z#; Maximum
```

Is this value smaller than your new Z Endstop Value?

{% tabs %}
{% tab title="YES" %}
This value MUST be at least 0.5 mm above your calibrated Z Endstop Value.

Add 0.5 mm to your new Z Endstop Value. This is your new Maximum Z Value.

Change the Z value to the new Maximum Z Value.

Click "Save Changes"

Home the Z.

Check to see if your Z Endstop Value is correct.

If not, continue reading.
{% endtab %}

{% tab title="NO" %}
Continue reading. 
{% endtab %}
{% endtabs %}

#### Your mesh compensation may be changing the value.

Home the Z.

Run:

```
G29 S2
```

The Z Endstop Value should now be the calibrated value.

Mesh compensation is changing the value of your Z Endstop Value. 

Proceed with printer operation.


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://promega.printm3d.com/how-to-troubleshoot/homing.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.