Lexmark 31.40 missing or unresponsive toner cartridge

Can you keep using it?

Contact customer support if any of these apply

!31.40 remains after reseating a genuine toner cartridge.
!The printer repeatedly loses cartridge recognition after restart.

If the printer still starts normally: Finish the first checks once, then stop if the same message repeats or the printer still cannot return to ready.

What to check first

Step-by-step checks

1
Consumable check
Remove and reinstall the toner cartridge carefully.
Start with the official recovery step before moving on to parts or deeper servicing.
2
Consumable check
Confirm the cartridge is a genuine Lexmark supply.
3
Safe first step
Check printer date, time, and firmware if the message returns.

Background

What this message usually means

Lexmark uses 31.40 when the installed toner cartridge is missing or unresponsive. On this office mono family, the usual first checks are genuine-supply verification, careful reseating, and then date, time, and firmware checks if the message persists.

Diagnosis

Likely causes

Most common

The toner cartridge is not fully seated.

Common

A non-genuine or defective cartridge is not responding.

Possible

Firmware or printer date and time state is contributing to the supply check.

Service

When service or replacement is more likely

-This is a supply-recognition problem, not a paper-path jam.

Related codes in this family

29.xx

Packing material is still present on one or more installed supplies.

31.60

The imaging unit is missing or not responding correctly.

Explore more

More Lexmark printer families

MS / MX series

MS310, MS410, MS510, and more.

CS / CX 310 / 410 / 510 series

CS310, CS410, CS510, and more.

Source notes

Lexmark's official 31.4x guide says 31.40 is a missing or unresponsive toner-cartridge error and recommends genuine-supply checks, reseating, and firmware review.

Built around official Lexmark user-guide and service-manual material for the MX431 and closely related mono office models. Exact code behavior can vary a little by print-only versus MFP model and installed options, but the main paper-jam and supply messages stay close across the family.

Printer error codes can vary a little by firmware, region, and exact model variant. Use this guide as a family-level starting point and stop if the next step would require disassembly or service-mode changes.

Known family variants: MX431adn, MX431adw, MS431dn, MS431dw, XM1342

Last reviewed: 2026-04-12

Reference: Open reference

31.40 - The toner cartridge is missing or not responding correctly.