ER18 - Print head communication error

In case of the ER18 error, the following message appears on the Ultimaker 3 display:
There is a communication error with the print head.

The PCB inside the Ultimaker 3 print head has information about the print cores, the active leveling sensor, and the fans. This information is sent to the electronics at the bottom of the printer via the white print head cable.

This error message indicates an interruption in the communication between the print head and the mainboard. Often, this is caused by a poorly connected print head cable. The cable may have gotten loose during transport, rough manual handling of the print head (for example, when removing the Bowden tube), or over time during many printing hours.

Reseating the print head cable

In most cases, the problem can easily be resolved by reseating the print head cable. This will only take a few minutes. Follow the steps below, or watch this video by our North American support partner:

Note: Turn off the printer and disconnect the power cable before you start.

UM3-Reseat-print-head-cable-1.jpg UM3-Reseat-print-head-cable-2.jpg
1. Remove print head screws 2. Remove cable cover*

Use the 2 mm hex screwdriver to remove the two long screws from the back of the print head. These secure the small plastic print head cable cover.


Older style print head cable covers must be clicked off. Insert a (flat-sided) screwdriver into one of the slots, or into one of the screw holes. On newer print heads, slide the cover straight upwards.
* see note below


UM3-Reseat-print-head-cable-2.jpg UM3-Print-head-cable.jpg
3. Loosen print head cable 4. Inspect the cable

Slightly pull back the cable and insert the screwdriver into the print head. Gently push the connector's clip to release the print head cable.


Remove the print head cable from the print head and carefully inspect it for damage. Check that all 10 wires are still fully inserted in the connector. If so, reseat the cable. If not, replace it.




5. Reseat the print head cable

6. Close the print head

Firmly push the cable into the connector again. You should hear it click into place. If necessary, carefully push on either side of the white connector with the screwdriver.

Place the cable cover back onto the print head. Insert the two long screws and tighten them. Be careful not to overtighten these bolts; this will increase the stress on the bearing and reduce its lifespan.


Print head housing improvements

Print head communication errors can be more frequent on older Ultimaker 3 models (2016-2017). In 2018, Ultimaker made several changes to the print head housing to improve the strain relief and grip on the print head cable:

Print-head-cable-connection-old.jpg Print-head-cable-connection-new.jpg

Old cable cover, with shorter strain relief and straight connector.


New cable cover, with longer strain relief and slotted connector.


If your printer is still equipped with the older style print head housing parts, contact support or your local reseller to enquire about replacement parts.

Note: If problems persist after taking the steps on this page, it is likely that your print head cable should be replaced. Contact support or your local reseller for further assistance. Ensure to include the error number and the log files of your printer.

Was this article helpful?
38 out of 111 found this helpful



Article is closed for comments.