If you have an HP LaserJet P2015 (P2015n or P2015dn), you might run into a problem where the paper jam light stays on or where you have to constantly power cycle the printer to make it print. This could be because of a faulty formatter board that needs to be replaced (which is a common issue with this model printer). One method that might work for you is preforming a Super nvram initz.
How To Preform A Super NVRAM Initialization
1. Turn off the printer.
2. Press and hold the Go button.
3. Turn on the printer and continue to hold the Go button for at least 50 seconds. During this process, the Attention, Ready, Go lights turn on. Then the Attention and Ready lights turn off, leaving only the Go light illuminated.
4. Release the Go button. The Go, Ready and Attention lights turn on.
5. Press and hold the Go button. All lights turn off. During the next three seconds, the Go, Ready and Attention lights turn on in that order, one per second.
6. Release the Go button to perform the initialization. The control panel lights begin cycling from front to back. After the Super NVRAM initialization process is complete, the printer returns to the ready state.
This can be a little tricky. During step 5, I had to press and hold the Go button a couple of times before I got the three lights to flash.
Once it starts, the printer will slowly feed some paper through, then it’ll return to the ready state.