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Lexmark T640

Lexmark T640

A "Toner Low" message appears on operator panel

Message: " 88 Toner Low "; Message: " Replace Toner "; Blank pages; No print on the page; Light print; Washed-out print; Poor print quality; Faded print

What you will see

The printer will display a Toner Low message on the operator panel. This warning will appear when the toner cartridge is nearly out of toner (typically down to its last 10 or 15 percent). To see approximately how much toner is left, print out the Printing the Menu Settings Page. Check the Toner Level setting printed on the last page. If the toner level reads Low or is below 15% of the bar, the cartridge is near the end of its life and should be replaced soon.

What to do

When the Toner Low message first appears, have a replacement toner cartridge available. Follow the instructions below as appropriate.

Install a new toner cartridge

In most cases, the toner cartridge is low on toner and needs to be replaced. Power off the printer. Replace the toner cartridge in the printer with a brand new one. (For more information on how to replace a toner cartridge, How to Change the Toner Cartridge on a Lexmark T64x Series Printer.) Power on the printer and try printing again. This should clear the message.NOTE: If you feel the current cartridge failed long before reaching its expected yield and it is an original Lexmark toner cartridge that has not been refilled or reworked in any way, please contact Lexmark Technical Support. See 'Contacting Lexmark' at the end of this document for more information.

If a new cartridge is currently unavailable

If a replacement toner cartridge is unavailable, you can continue using the printer while this message is displayed. Simply press the check button to clear the message. If you begin to experience print quality issues, such as light or missing print, remove the print cartridge and lightly shake it back and forth to redistribute the remaining toner. The number of pages that can be printed with acceptable quality after a Toner Low message appears will vary depending on factors like paper size, darkness settings, and toner coverage per page. When the current toner cartridge can no longer print satisfactorily, it will need to be replaced.

Replacing the cartridge does not clear the message

If you replace the toner cartridge and the Toner Low message remains, the printer may need to be reset. Power off the printer. Let the printer sit 20 to 40 seconds and then power it back on. If the Toner Low message does not appear on power-up, try printing again. If the Toner Low message returns on power-up or when printing, confirm the following: If you install a brand new Lexmark toner cartridge and the Toner Low message remains, the printer may require service to correct the issue. Please contact Lexmark Technical Support or a local authorized service provider for more information. See 'Contacting Lexmark' below.

  • The cartridge you just installed is a brand new toner cartridge and not a used one.
  • You are using an original Lexmark brand toner cartridge. Cartridges manufactured by a third party may not be compatible with the printer. If a third-party cartridge is causing this issue, contact the point of purchase for additional support or replacement of the toner cartridge.
  • The toner cartridge has not been refilled or refurbished. If the cartridge has, contact the place where it was refilled to have it replaced.

Contacting Lexmark

If none of the above suggestions resolves the issue, or if you need help arranging service, please contact Lexmark Technical Support for additional assistance.If you call Lexmark Technical Support for assistance with your printer, please be prepared to describe the problem you are experiencing and any troubleshooting steps you have already taken.. This information can be found on a label located on the inside of the printer, under the upper front cover.Please call from near the printer in case the technician asks you to perform a task involving the printer.


  • Toner sensor assembly - Part #40X0036
  • HVPS/toner sensor cable assembly - Part #40X0223

If the error continues after replacement of the toner sensor and the toner sensor cable, try replacing the system board assembly (see below for the applicable part number).

  • 40X3459 - System board assembly (non-network), T640 (4061-000)
  • 40X3460 - System board assembly (network), T640n (4061-010)
  • 40X3461 - System board assembly (non-network), T642 (4061-200)
  • 40X3462 - System board assembly (network), T642n (4061-210)
  • 40X3463 - System board assembly (non-network), T644 (4061-400)
  • 40X3464 - System board assembly (network), T644n (4061-410)

IMPORTANT! The part numbers listed here are correct as of November 2006. Please confirm that they are still current and valid before ordering. If the part numbers do not work, please see your next level of support or contact Lexmark Technical Support for the current part number.

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