Kyocera error code Replace MK.
Quick answer
The maintenance kit is due. Kyocera documents replacement of the maintenance kit parts as necessary every 100,000 pages of printing, and states that it requires professional servicing — the guide's instruction is to contact your service representative rather than to fit it yourself. Like other page-counter messages this is a scheduled interval, not a detected failure.
Hazard: This step carries a risk of injury or permanent damage. Power the printer off, let it cool, and check your model's manual before opening any panel.
Before you try the solution
- 1. Copy the complete message exactly as shown, including any letters, spaces, or punctuation around Replace MK..
- 2. Find the printer's exact model number. The same-looking code can mean something different on another model family.
- 3. Let the current print, scan, or update operation stop before touching controls, paper paths, or covers.
Manufacturer-documented solution
The maintenance kit is due. Kyocera documents replacement of the maintenance kit parts as necessary every 100,000 pages of printing, and states that it requires professional servicing — the guide's instruction is to contact your service representative rather than to fit it yourself. Like other page-counter messages this is a scheduled interval, not a detected failure.
Model scope: the troubleshooting section of your own model's Kyocera operation guide — the page interval is model-specific. 100,000 pages is documented for the ECOSYS M2135dn, M2635dn, M2635dw, M2040dn, M2540dn, and M2540dw
If the error is still there
- 1Return to the screen or job that produced the message and check whether the code has cleared.
- 2If Replace MK. returns, do not repeat a risky procedure. Record when it appears and check the documentation for the exact model.
- 3Because this message involves opening the printer, service risk, or possible damage, stop and contact Kyocera support or a qualified printer technician if it persists.
Other Kyocera error codes
- Replace the toner.The toner container is empty and must be replaced. Kyocera documents an earlier, separate message — "Toner is low. (Replace when empty.)" — which is a warning that the container is nearing its end, not an instruction to change it yet. Waiting for the replace message avoids discarding usable toner.
- 1102"Login Username and/or Password is incorrect" for the scan-to-email/SMB destination credentials — a specific scan-job authentication failure, not a general network connection failure.
- Cannot connect.The Wi-Fi or Wi-Fi Direct connection did not complete. Kyocera's documented action is to check the settings and the signal conditions. This is a wireless-association failure at the machine, distinct from the authentication-server messages that appear when the network is fine but a credential or the machine's clock is wrong.
- Cannot connect to Authentication ServerThe machine reached the point of authenticating and failed. Kyocera documents four distinct variants with different checks: verify the connection status with the server, check the domain name, check the host name, and set the machine's time to match the server's time. The clock variant is the one that surprises people — an authentication server will reject a machine whose time has drifted, even though every name and password is correct.
- Low temperature. Adjust room temp.The room is too cold for the machine to operate within specification. Kyocera's documented action is to adjust the temperature and the humidity of the room. Worth knowing before a cold-garage or unheated-office machine is diagnosed as faulty.
- Machine failure. Call service.An error has occurred in the machine. Kyocera's documented instruction is to make a note of the error code shown on the message display and contact your service representative. This is the guide's answer for numeric machine faults generally: Kyocera does not publish the meanings of individual C-codes to users, so the code is information for the technician rather than something to act on yourself.
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Manufacturer reference
The meaning and documented action above were taken from the manufacturer source below.
Operation Guide — ECOSYS M2135dn/M2635dn/M2635dw/M2040dn/M2540dn/M2540dwVerified against manufacturer documentation, last checked 2026-08-15. PrintDiag has no printers and no technician, so nothing here is claimed as tested on hardware.