Toner light stays on after I changed cartridge

Make sure you turn the printer off and back on a couple times. The fuser is not "hot-swappable"meaning you need to cycle the power for the machine to recognize it. If after doing this and you are confident that the fuser is seated correctly the next step would be to replace the fuser (part# - 115R00035). ItemInc.com has these in stock and ships same day. Hope this helps and thanks for using FixYa!

This is a pretty common item, usually for HP printers however I've also seen this with non-HP printers. They REALLY want you to use genuine HP or Dell ink/toner in their printers since they make lots of money on consumables. That being the case, there is a chip on most original (OEM) toner cartridges that tells the printer that its a genuine cartridge. If you purchase aftermarket/remanufactured/3rd party toner to save a few dollars, they frequently don't have these chips, however other than that they work just fine.
If you have purchased a Staples/Office Max or some other non Dell branded toner, that's likely what happened. My suggestion is to live with this minor annoyance and just wait until the print begins to get lighter in color. THAT will be your indication that its about time to change the toner.
If you get this same issue with a new Dell branded toner, then you may want to try to find this chip and use a pencil eraser to carefully clean the electrical contacts on the toner cartridge. That may help the printer read the cartridge chip easier.
Hope this helps! Best of luck!

I had a similar problem in that after changing one of the cartridges (I bought a whole set), the message "cannot rotate cartridge" appeared. I tried pressing the cartridge in more firmly and may have caused the carousel to rotate a little in the process. I cycled the power which seemed to clear the error message and allowed me to select the next cartridge to change, but upon opening the door to change it, was unable to remove the old one as it was positioned a little too high. I eventually cleared the problem by manually rotating the carousel by pressing in and holding the carousel release (see arrow) while rotating the carousel downward slightly, to line the cartridge up as it appears in this picture. Then powered it back up and was able to do the normal cartridge replacement procedure for the remaining cartridges without further error messages.

1. Open the top front cover of the printer. If the display DOES NOT read Close cover or Insert cartridge, the 32 error is not caused by the toner cartridge and printer service will be required to fix the problem.

2. Make sure the correct toner cartridge is installed for this printer model.
1. Check Lexmark for a list of compatible cartridges for your printer.
2. If the wrong toner cartridge is installed, remove it and install the correct one.

3. If the correct toner cartridge is installed, it may not be seated correctly. To ensure that this is not the cause of the error, do the following:
1. Turn off the printer.
2. Reseat the toner cartridge.
3. Close the lid.
4. Power the printer back on and check the display.

4. If reseating the toner cartridge does not clear the error message and the error started as soon as you installed this particular toner cartridge, the cartridge may be broken. You can check this as follows:
1. Power off the printer and then reinstall the old cartridge. (You can also try a different new cartridge to see if that clears the error.)
2. If the error does disappear, the problem may lie with this cartridge. Please contact the point of purchase, especially if the cartridge is brand new out of the box.

5. If the error cannot be cleared by putting in a new toner cartridge or one that is known to be working, the printer may require service to fix the problem.

This error message appears on the printer screen when the printer thinks the wrong toner cartridge is installed. To clear it or identify a service requirement, follow the steps below. NOTE: If you succeed in resolving the problem at any stage during the procedure, you not need to perform the remaining steps.

1. Open the top front cover of the printer. If the display DOES NOT read Close cover or Insert cartridge, the 32 error is not caused by the toner cartridge and printer service will be required to fix the problem.
   
   
2. Make sure the correct toner cartridge is installed for this printer model.
   1. Check Lexmark for a list of compatible cartridges for your printer.
   2. If the wrong toner cartridge is installed, remove it and install the correct one.
      
3. If the correct toner cartridge is installed, it may not be seated correctly. To ensure that this is not the cause of the error, do the following:
   1. Turn off the printer.
   2. Reseat the toner cartridge.
   3. Close the lid.
   4. Power the printer back on and check the display.
      
4. If reseating the toner cartridge does not clear the error message and the error started as soon as you installed this particular toner cartridge, the cartridge may be broken. You can check this as follows:
   1. Power off the printer and then reinstall the old cartridge. (You can also try a different new cartridge to see if that clears the error.)
   2. If the error does disappear, the problem may lie with this cartridge. Please contact the point of purchase, especially if the cartridge is brand new out of the box.
      
5. If the error cannot be cleared by putting in a new toner cartridge or one that is known to be working, the printer may require service to fix the problem.

TONER CHIP on CP2025 printer:
This resource may help
http://resources.lasertekservices.com/hp-smart-chips-overriding-this-lockout-mechanism-with-reset-chips/
Gives types of chips to use, sales in USA, and certain things to take note of.
The toner reset chip replaces the original HP ID chip and is designed to be used only on refilled HP cartridges.
It is not recommended to force toner cartridges to run on empty, as this can cause damage to both the printer and the toner cartridge.
The reset chips are dedicated to one color only, so that user can not swap toners.
As for actual physical installation, just push the new ID chip in until it clicks into place. The correctly manufactured ones should be a snug fit.
I have seen techs using a drop of contact glue behind the chip-board to secure it.
Copper pads face outwards towards matching printer pins.
See photo for polarity 'square' pad.
My printer is Samsung, not HP, so your toner cartridge may be a different shape.

I found this and it worked great.

1. Power Unit off

2. Open front cover

3. Press and hold GO and turn power on

4. When all 3 lights lit release and press GO twice

5. All lights turn solid

6. With all solid, press GO 5 times

7. Ready light GOes red

8. Close door and you're all set

There are two contact on the right wall off the printer cartridge chamber area. They can get pushed in causing the printer cartridge to not read correctly. Take a small Flathead screwdriver and bend them up so the cartridge ink level can be read.

Check the transfer roller. Its a black spongy roller in from of the drum. Make sure it is getting good contact. Did you shake the toner cartridge before you installed it?

The error is "toner cartridge error" you could try cleaning the contacts inside the printer (with the power off, of course). If that doesn't work you will need to try another cartridge.