Error code 942.01 ??? what does this mean? service yellow TMC

SOURCE: What does an error code H4-01 mean on a Sharp

Fuser Heater failure. The fuser is the part of your machine that heats up and "fuses" the toner onto the paper. It is located right near where the paper exits the copier. This error code means that the fusing unit is not heating up as it should. The most common failures in order of ocurance are thermal fuse, thermister and heater lamp. In any case you are going to need a service person to come out and diagnoe which part has failed, replace the part and reset the code for you. Should not be more than say $200 to repair.
Good Luck and Thank You for using Fixya.
WheatlandServices

SOURCE: 942.02 Service Yellow TMC Sensor

Remove the toner cartridge, and inspect the lenses on the toner meter cycle (TMC) card.It is positioned on the right side of the toner cartridges
Are the lenses blocked, or dirty? Clean them
If damaged replace them

SOURCE: What means "943.02 Service Black TMC Sensor"?

A 94x.xx TMC Error indicates that the printer has failed to detect the Toner Metering Cam for a specific cartridge. This error typically occurs when the cartridge or developer are misaligned or incorrectly seated

Please click on the link http://bit.ly/ozldpC to see instructions on how to go about the procedure.

For further assistance, please contact Lexmark Technical Support.

SOURCE: tHE 942.02 Service Yellow TMC Sens message is in

Error indicates a problem with the Cyan toner cartridge/developer. Try the following steps:
Power off the printer/MFP and open the toner access door. Reseat all of the toner cartridges. Power on the printer/MFP again and print a test page. Did the error message return? Power off the printer/MFP and remove the developer unit for the color specified in the error message, and then reseat it. Try printing another test page, verify if you're still getting the same error. It is possible that specified color's toner cartridge and developer unit are defective. If you have a replacement toner cartridge and developer, install them as a test and print a trial page.

For further assistance, please contact Lexmark Technical Support Center.