Dell 2135 cn Color Laser MFP getting a CDT Sensor Error

The solution to this problem is to do the following:

1. Power the printer off
2. Open the front cover of the printer by clicking the button on the side
3. When the front cover comes down, locate the transfer belt in the center (looks like a roll of file)
4. at the top of the transfer belt you will see a rectangular silver plate (called the transfer CDT transfer sensor)  this approximately 1/2 inch long and 1/4 inch wide
5. Take a dry q tip squab (no alcohol, water etc.) and clean the item and the sleeve across the top of the belt (you should see a lot of toner on the qtip)

Once you are done cleaning the transfer sensor, turn the printer back on

This should clear up the problem and the error should go away.