Description: PTC heater. Don't know what this is, but "0" means it is not installed. 1 means it is.
Description: Power leakage of some kind. Heat, exposure, AC or power supply or main relay. Go to "25 mode" and select "P49" and reset to "0"
Description: Toner motor
Description: Toner density adjustment problem. This means the machine is undertoned. To repair, replace developer and enter "47" mode. Press 51. Press print. Allow the machine to cycle until it stops. Some feel you should disconnect the toner motor first. This code happens probably because either the machine wasn't set up properly, or because the customer kept using the machine with the light on.