This printer prints beautifully from tray 2, but when sourced from tray 1 the only thing it produces is a "Tray 2 Jam" and will not print until you go through the motions of clearing an imaginary jam. The pickup roller never rotates. Everything I can find on this says it is a Firmware error. I have installed and re-installed the latest firmware (FW date: 20150126) with no change in the symptoms. It has been tested with external and internal prints with the same results.
So far I have swapped out the Driver PCA, Formatter and DC controller with known goods. Have reset all settings to factory defaults and tried all combinations of tray and paper settings. I have verified that the tray 1 pick up roller drive is working by going to the secondary service menu choice to rotate the roller. I have looked for older firmware in order to downgrade it, but I only find the current version. Also in the secondary service menu under Service Reports/Error Report shows the following error:
Hello. I also found this problem in my LaserJet Pro 400 Color M451dn. Did't troubleshoot it that deep but symptoms are exactly the same. There is not much about that in Internet, but it seems the bug is common for the model