HP P3015 Service manual. 49 code diplays intermittanly.

[prntrfxr]

90% of the time they are caused by corrupted data from clients PC's. Just clear the print queue and continue. Sometimes it is software conflicts
Sometimes they just need to update drivers. When IT updates software and leaves same drivers they can have issues. I've also seen clients use older drivers from other machines. (Client printing to a P4015 using a 4200 driver.) They complained that, "it worked before". This may be true but if they have updated other software or firmware on the printer it may no longer work. Best to have the same driver for the printer installed (universal drivers are different).
Sometimes firmware update is needed.

8% of the time they have an issue with cabling

2% of the time there is a problem with network card/formatter

[Desert Rat]

Thank you for those statistics. I'll make a note of this for future reference.

DR