HP Officejet Pro 251dw Printer series - Manual (Page 144)

Solution: Click OK to continue printing or replace the cartridge. For information about how to
install new cartridges, see Replace the ink cartridges.
Problem with printer preparation
The printer clock has failed and ink preparation may not be complete. The estimated Ink Level
gauge might be inaccurate.
Solution: Check the print quality of your print job. If it is not satisfactory, running the printhead
cleaning procedure from the toolbox might improve it.
Ink sensor failure
The ink sensor has failed and the printer can no longer print.
Contact HP support. For more information, see HP support.
Problem with ink system
Please remove the ink cartridges and examine them for any sign of leaks. If any cartridges have
leaks, contact HP. Do not use cartridges that are leaking.
If there are no leaks, re-install cartridges and close the printer cover. Turn the printer off then on
again. If you get this message a second time, contact HP.
Appendix F
140 Errors (Windows)