Hi.
PP is the code for a paper jam, so it basically means the printer is not sensing roation, or it is running too slow. normally, you just clear the paper path of any problems, then turn it off at the wall for a few seconds (while still in REG mode), then turn it back on, and it should correct itself. If not, then it may have motor or sensor problems. A motor drive IC fails in some models and it causes this symptom.
Hope this helps.
Mark, August 2008