Update firmware to the latest version.
For example, make sure firmware is at EC6 (LW60.xx.P632) or EC6.1 (LW61.xx.P634), and engine code is at FDN.PIR.E636.
Set engine setting 9 to 2 (decimal).
From the control panel:
Boot into the Diagnostics Menu. a. Turn the device off. b. Hold down both 3 and 6 buttonswhile turning the device back on. c. Release 3 and 6 when you see the progress bar is half way across the initial "Lexmark" splash screen.
The device will then boot itself as normal.
Once in the diagnostics menu, select Printer Setup.
Select Engine Setting 9.
Enter 2 for the new decimal value, and submit the change.
Verify that under Printer Setup, the Engine Setting 9 has a value of 2.
Press the back button repeatedly until you return to the main Diagnostics Menu screen.
Select Exit in the lower right or left corner of the panel to exit the Diagnostics Menu. (Button location based on model)
Before running the OM Plus* calibration, perform a full reboot with the power switch.
Do not rely on the reboot that happens when exiting the diagnostic menu or the auto-reboot after applying the npa file.
Why? This is to prevent an engine re-calibration on the device to a previously known performing state.
Note: A device reboot is not needed if you have just replaced a supply (toner cartridge or imaging unit) since an engine calibration is forced when a new supply is installed.