The "994 Density Sensor" Error Message indicates that the printer's System Card has encountered an unrecoverable error. A broken Density Sensor Finger (which is located in the Front Door) or a broken Density Sensor Actuator in the printer, can both cause this issue. If the Transfer Belt has recently been replaced, please check whether the Density Sensor Finger and Density Sensor Actuator are in proper position.
This error normally requires a service call, especially if issue is cause by a broken Density Sensor Finger or a broken Density Sensor Actuator. However, certain rare occurrences, such as a power fluctuation, or a stray static discharge in the vicinity of the printer, can cause a false 994 Density Sensor error message to display. In such cases, the error is only temporary and can be easily resolved without service. Please follow the steps in the table below.
NOTE: To navigate through the menu options, i.e., [ ], use the Left , Right , Up  and Down  buttons; to select an option, use then press the Check  button to select it.
|Step||Action||Click Image to Enlarge|
Power the printer off, wait for 30 seconds, and then power the printer back on.
Yes: Continue to Step 2 or go to Contacting Lexmark.
If possible, connect the printer's power cord directly into a grounded wall outlet. In rare instances, a surge protector or uninterruptible power supply (UPS) can generate false error messages.
Yes: Continue to Step 3 or go to Contacting Lexmark.
|3||Open the Front Door and check if the Density Sensor Finger is broken (see right-hand image). If it appears to be broken, please go to Contacting Lexmark.|
|4||While Front Door is open, ensure that the Density Sensor Actuator is in the proper position (see right-hand image). If it appears to be broken, please go toContacting Lexmark.|
Ensure that Front Door is fully closed.
Yes: Continue to Step 6 or go to Contacting Lexmark.
|6||Power the printer off, and press and hold the Down Arrow  button and the Right Arrow  button.||No Image|
Power the printer back on while holding these buttons down. Then release them when the Performing Self Test displays on the screen.
Note: The message Diag Menu will display on the screen. If it does not display, please repeat Step 6 or go to Contacting Lexmark.
Using the Navigation Keys, select Print Tests, then select Prt Quality Pages.
Note: If any of the pages is missing half a plane of color, or if the center of the page (Portrait) is a void, it will cause a 994 Density Sensor. Please go to Contacting Lexmark below.
Did the error message return?
Yes: A service call will likely be required to resolve the issue. Continue to Contacting Lexmark.
To exit from Diag Menu, press the back button and select Exit Diags.
Please contact Lexmark Technical Support for additional assistance. NOTE: When calling for service you will need to know your printer model type and serial number (SN). If you need help locating your printer's model type and serial number, click here.
Please call from near the printer in case the technician asks you to perform a task involving the printer.