Ender 3 (Pro & V2 & S1 & Neo) Auto Homing Off the Bed – Causes & Fixes

While noticing that your Ender 3’s printhead is positioned out of the bounds of the print bed after the auto-homing process can definitely be a confusing situation to come across and even make you think that your 3D printer may end up printing in the air, there can be a reasonable explanation for this in some cases.

In this guide, we will discuss whether your Ender 3’s printhead ending up off the bed after the auto-homing process poses a problem for your prints, explain the factors that can create such a scenario, and take you through a step-by-step guide that you can follow to resolve this issue as swiftly as possible in situations where this would indeed be problematic.

What Can Cause the Ender 3 (Pro & V2 & Neo & S1) to Auto Home Off the Bed?

Before we move forward with the factors that can cause an Ender 3 to auto home off the bed, we need to mention one case where this may not be a problem and hence, won’t require you to fix anything, as it can potentially save you from a lot of troubleshooting that wasn’t even necessary, to begin with.

While the auto-homing process is usually (wrongly) associated with finding and moving to the X0 Y0 (and Z0) point, what auto-homing (only the X and Y axes, in this case) actually does is to locate the X and Y endstops and consider the current X-axis and Y-axis positions to be X_MIN_POS and Y_MIN_POS (which are set to 0 by default, but this can be incorrect), respectively, once it reaches the point where both endstops are triggered.

x min pos and y min pos variables in marlin config


So, in a case where any of the endstops are positioned in a way that causes the printhead to be off the bed once triggered (there usually is a distance between the X endstop and the print bed by default), the auto-homing process, unless configured to explicitly move to any other location afterward, (such as when Z_SAFE_HOMING is enabled), will cause the nozzle to be positioned off the bed, which is actually standard behavior.

example of printhead being positioned off the bed


Provided that the X_MIN_POS and the Y_MIN_POS parameters are configured correctly in Marlin firmware, the nozzle being off the bed after auto-homing won’t pose a problem for the success of your prints, as it will still mean that your Ender 3 knows that the nozzle is currently off the bed at the printhead’s current position, which will be signified by the off-the-bed axis having a negative value at that location, such as X=-5 for the nozzle being 5 mm away from the bed on the X-axis.

x min pos negative example


So, if this is also the case for you, we highly recommend manually moving the printhead to X0 Y0 after the auto-homing process and seeing whether it is off the bed before moving forward with this guide, as you won’t have any issues with your prints as long as the printhead is correctly positioned at the front-left corner of the bed at X0 Y0.

On the other hand, if the screen shows that the printhead is positioned at X0 Y0, regardless of whether it went there automatically after the auto-homing process or moved manually, and the nozzle of your Ender 3 is still off the bed, you have a problem on your hands that you will need to fix, which is what we will cover in this guide.

With that mentioned, it’s time to dive into the factors that can cause your Ender 3 to auto home, or rather, have its X0 Y0 position off the bed.

Incorrectly Configured X-Axis and Y-Axis Minimum Positions

The first problem that can cause your Ender 3’s nozzle to end up off the bed after auto-homing and moving the printhead to the X0 Y0 position is an incorrectly configured X-axis or Y-axis minimum position value.

x min pos misconfiguration example


Under normal circumstances, the X-axis minimum position (X_MIN_POS) is supposed to signify the position of the nozzle when the printhead triggers the X-axis endstop, and the Y-axis minimum position (Y_MIN_POS) is supposed to signify the position of the nozzle when the printhead triggers Y-axis endstop, in your Ender 3’s firmware configuration.

Combined with the fact that the nozzle should be right on top of the front-left corner of the print bed when your Ender 3 is positioned at X0 Y0, we can practically think of X_MIN_POS as the distance between the nozzle and the left edge of the print bed, and Y_MIN_POS as the distance between the nozzle and the front edge of the print bed at the point where both endstops are triggered.

So, for instance, if the nozzle is 3 millimeters off the bed from the X-axis where the X endstop is triggered and 1 millimeter off the bed on the Y-axis where the Y endstop is triggered, the correct X_MIN_POS would be -3, and the correct Y_MIN_POS would be -1, signifying that the position where both endstops are triggered is X-3 Y-1.

example of correctly configured x and y min positions


On the other hand, in a case where the X_MIN_POS and Y_MIN_POS values don’t correctly reflect these distances, particularly when their values are higher than they should actually be, the nozzle won’t move close enough to be on top of the bed, as the firmware doesn’t have any other way of knowing the distance between where the endstop is triggered and where the print bed starts.

Continuing from the previous example, if X_MIN_POS and Y_MIN_POS were misconfigured, for instance, with an X_MIN_POS value of -1, and a Y_MIN_POS value of 0, the nozzle would be positioned off the bed by 2 mm on the X-axis, and 1 mm on the Y-axis at X0 Y0, putting it completely off the bed, as the firmware will think that the position where both endstops are triggered is X-1 Y0 when it should be X-3 Y-1.

example of incorrectly configured x and y min pos avariables


Misconfigured X-Axis and Y-Axis Home Offsets

Another issue that can end up with your Ender 3’s nozzle ending up off the bounds of the print bed at the X0 Y0 position is the X-axis and Y-axis home offsets being misconfigured, which you can modify with the M206 (Set Home Offsets) and M428 (Home Offsets Here) G-code commands or the LCD controller of your Ender 3 through an option labeled Set Home Offsets.

x axis home offset misconfiguration example


When X-axis and Y-axis home offset values are defined, the firmware subtracts these values from the coordinates that are a part of any movement command that your Ender 3 runs (with absolute positioning), essentially changing the position of the entire coordinate plane by shifting it toward either side based on the sign of the offset values.

While the way home offsets work isn’t exactly the same as the minimum positions (which is why using them can lead to print area restrictions in some cases), their purpose is also to correct the positioning of the nozzle relative to the print bed and make it so that the nozzle is located correctly on the front-left corner of the print bed at X0 Y0.

For instance, if your Ender 3’s nozzle ends up being 4 mm away from the bed on the X-axis and 3 mm away from the bed on the Y-axis at X0 Y0, you can quickly correct this mistake by shifting the coordinate plane 4 millimeters to the right, and 3 millimeters to the back, which will practically make X4 Y3, which is the location where the nozzle is right on top of the front-left corner, the new X0 Y0, as it should be.

To perform such an adjustment – you would need to set the X-axis offset to -4 and the Y-axis offset to -3, which you can get done using the M206 X-4 Y-3 G-code command.

example of how correctly setting home offsets work for x and y axis


Continuing from the previous example, if you end up making the wrong adjustment, such as setting both the X-axis offset and Y-axis offset to -2, you would effectively be turning X2 Y2 into the new X0 Y0 instead, in which case the nozzle would still be off the bed by 2 mm on the X-axis and 1 mm on the Y-axis.

example of setting x and y home offsets incorrectly work for x and y axis


Wrong Usage of G92 (Set Position)

Finally, while less likely to be the one causing the problem than the previous two culprits, the wrong usage of the G92 G-code command can also be the thing that causes your Ender 3’s printhead to position itself in a way that causes the nozzle to be off the bed at X0 Y0.

wrong usage of the g92 g-code command example


The purpose of the G92 G-code command, in the case of the X and Y axes, is to change the X-axis and Y-axis positions of your Ender 3 by manually specifying the coordinates it’s currently located at, which practically overrides the actual position data and replaces it with your input.

Unlike the two factors we have talked about earlier, G92 is only a temporary adjustment (you can’t save it to the EEPROM but can add it somewhere, such as the Cura Start G-Code section, to run it before each print if necessary) under normal circumstances, and the usage of the G92 command is not limited to correcting the positioning of the X and Y axes, with resetting the extruder while it’s in relative mode being perhaps its most common form of usage.

Regardless, if your Ender 3 ends up unwarrantedly running the G92 G-code command with values that would throw the positioning of the X and Y axes at any point, which would usually be due to an oversight during slicing, such as using a plugin that adds such behavior, the nozzle can end up off the bed at X0 Y0.

For instance, if the nozzle of your Ender 3 was correctly positioned on the front-left corner of the print bed at X0 Y0, but then the command G92 X2 Y2 ends up running, the front-left corner of the bed where the nozzle has been sitting will now become the X2 Y2 position, which will push the X0 Y0 position off the bed by 2 mm from each side.

Following the same example, fixing the positioning would require you to run the command G92 X0 Y0 without moving the nozzle, which will correctly set the front-left corner as X0 Y0 once again, and the nozzle won’t end up off the bed at X0 Y0 as a result.

How to Fix an Ender 3 (Pro & V2 & Neo & S1) That Auto Homes Off the Bed?

If the firmware you’re using is configured in a way that brings your Ender 3’s printhead to the X0 Y0 position after auto-homing, and the printhead is off the bed at this point, you will need to correct this problem to be able to use the entirety of the print area and avoid a scenario where your Ender 3 ends up printing in the air.

To start off, open up a G-code file you have sliced with your text editor (Notepad should do the trick), and confirm that it doesn’t have any instances of G92 that can affect the X and Y axes by searching for strings such as G92 X and G92 Y.

If you come across such commands, go through your slicer settings and plugins that could potentially insert them into the G-code files you’re slicing and revert things to normal.

searching for g92 x as an example in a g-code file


Next, find out the X_MIN_POS and Y_MIN_POS values configured in the firmware you’re using by checking the Configuration.h file in the source code, and note these values.

x min pos and y min pos variables in marlin config


If the firmware you’re using allows you to see and modify the X_MIN_POS and Y_MIN_POS values directly from the LCD controller (for instance, you can find this feature in Professional Firmware for Ender 3 V2 & S1), reset both of them to 0 instead.

ender 3 v2 x y min position configuration menu


Once that’s done, reset your X and Y home offsets to 0 using the M206 X0 Y0 G-code command.

If the firmware you’re using has this option available in the menus, you can also use the LCD controller of your Ender 3 for the task.

While you won’t be able to use the M206 G-code command (or adjust home offsets from the LCD controller) if the firmware you’re using has NO_WORKSPACE_OFFSETS defined in Configuration_adv.h, this won’t be an issue as it means that the firmware is configured not to use home offsets at all, meaning they’re already 0.

setting x and y home offsets to 0 with m206


Next, auto-home your Ender 3’s axes using the G28 G-code command or the LCD controller, depending on whichever is more convenient.

ender 3 v2 auto home example


Once your Ender 3 completes the homing process, move the printhead by either using the G1 G-code command or the LCD controller towards the front-left of the bed and keep making adjustments until the nozzle is right on top of the front-left corner.

While this process can take some time moving the printhead back and forth, you should eventually find the correct spot by looking at the nozzle from different angles and making minor adjustments at the same time.

nozzle positioned correctly at front left of the bed at x0 y0


Once that’s done, note the current X-axis and Y-axis positions of your Ender 3 from the screen, as we will require them during the configuration process.

Now that we have finished the preparation stage, it’s time to make the correct adjustments to the firmware and solve the problem of your Ender 3’s nozzle ending up off the bed at X0 Y0, where two different paths of either modifying the X_MIN_POS & Y_MIN_POS values or modifying the X-axis and Y-axis home offsets are available to us.

While our recommendation would be to use the first method due to it being the optimal way of doing things (you can find an explanation regarding the reason here, which we highly suggest reading), the fact that it will require you to modify, re-compile, and re-flash the firmware to your Ender 3 (unless your firmware allows the modification of these values with the LCD controller, as we have mentioned earlier) may not make this method ideal for everyone, in which case the second method offers a more convenient solution that every user can apply without issues.

Configuring X_MIN_POS and Y_MIN_POS

As the X_MIN_POS and the Y_MIN_POS values determine the physical limits of the X and Y axes (along with X_MAX_POS and Y_MAX_POS), correctly configuring them will ensure that your Ender 3 has access to the entire span of the axes and knows exactly where the print bed is.

To find the correct values you will need to use, subtract the X-axis and Y-axis positions you have noted toward the end of the guide from the X_MIN_POS and Y_MIN_POS values you have noted at the start, and note the final values, which will be the values we need for the configuration process.

For instance, if the X-axis value you have found is 5, the Y-axis value you have found is 1, the X_MIN_POS value you have noted is -3, and the Y_MIN_POS value you have noted is -2, the result for the X-axis would be -8 (-3 – 5), and the result for the Y-axis would be -3 (-2 – 1).

If your firmware makes it possible to modify these values with the LCD controller (or with G-code), your work here is straightforward, as all you will need to do is navigate to the related area in the menus, make the adjustments, and save to EEPROM.

For instance, you can find the option to adjust X_MIN_POS and Y_MIN_POS in the Physical Settings menu, which is located in the Advanced section if you’re using Professional Firmware, or alternatively, use the C100 X### Y### G-code command to achieve the same effect.

ender 3 v2 x y min position configuration menu


On the other hand, if you’re using firmware that doesn’t allow these changes, your only option will be to change the X_MIN_POS and Y_MIN_POS variables accordingly in the Configuration.h file of the firmware’s source code, re-compile the firmware, and flash it again to your Ender 3 for the changes to take effect.

modifying the x and y min pos variables in marlin config


Additionally, while adjusting these variables, it can also be a good idea to double-check the values for X_BED_SIZE and Y_BED_SIZE and correct them if necessary (also X_MAX_POS and Y_MAX_POS if they already aren’t set to be the same as X_BED_SIZE and Y_BED_SIZE), as these variables define the extent of the print area, and their misconfiguration can end up with the print area being constrained or the nozzle coming off the bed from the other side during a print.

marlin x and y bed size config


Configuring X and Y Home Offsets

Configuring the X and Y home offsets allows you to shift the coordinate plane to either side for the X and Y axes, which, even when the travel limits are misconfigured, makes it possible to get your Ender 3 to position itself correctly in relation to the print bed.

In this case, you will only need the X-axis and Y-axis positions you have noted towards the end of the guide for the configuration process, as the X_MIN_POS and the Y_MIN_POS values will be left intact.

To modify the X and Y home offset values as conveniently as possible, our primary recommendation would be to use the M206 X-n Y-m G-code command, where n (-n -> negative n) refers to the X-axis position, and m (-m -> negative m) refers to the Y-axis position.

So, following the example from the earlier section, where the X-axis position was 5; and the Y-axis position was 1, you would need to use the command M206 X-5 Y-1, which will correctly set the X-axis offset to -5 and the Y-axis offset to -1.

Once that’s done, you will also need to save your modifications to the EEPROM, which you can quickly get done using the M500 G-code command.

That being said, if you already know where the option for setting the home offsets is in the menus and feel more comfortable using the LCD controller of your Ender 3 for the task, feel free to do so, as the effect will be the same in either case (don’t forget to save to EEPROM!).

Finally, while it’s possible to find an option labeled Set Home Offsets in certain firmware, this option actually runs the M428 G-code command behind the scenes, which, as opposed to letting you choose the offsets, automatically sets them in a way that causes the nozzle’s current position to become X0 Y0.

Please note that the Set Home Offsets option will also change the Z Home Offset by default, and to avoid this side effect, you will need to keep the Z-axis at 0 before clicking the button.

ender 3 set home offsets menu


In this case, you will want to take the nozzle to the front-left corner of the bed again with the X-axis and Y-axis values you noted earlier, click the Set Home Offsets option once the nozzle is at the correct position, and finally, save to EEPROM.

Please note that the M428 G-code command will only work if the current positions of the axes are within 2 cm of the endstops or the 0 point, meaning that you will need to use one of the alternative methods we have mentioned above if the distance is greater than 2 cm (20 mm) in your case.

Conclusion

As an Ender 3 that’s auto-homing off the bed can either be something that’s entirely harmless for your prints or the sign of an issue regarding the print area configuration, based on the coordinates the printhead ends up at after the auto-homing process, being aware of the differences between these two scenarios is critical to ensure that you don’t try to fix a problem that isn’t there.

Fortunately, even in a scenario where your Ender 3 auto homes off the bed due to misconfiguration, whether it’s the home offsets or the min/max positions, finding the culprit and applying the necessary fix should be a pretty straightforward process that will permanently ensure you don’t experience this problem again.