Jam In Print Paper Path MFP-M476NW

[rezz1777]

When turning on my printer I get the error message

"Jam in print paper path. Open rear door and clear jam."

However there is no paper jam. I have torn this printer apart and put it back together. And no paper anywhere.

When the printer starts up I hear the gear at the fuser motor (the one with the spring) skipping for a few seconds. So just to eliminate the fuser being the issue I have replaced the fuser however I still have the error message.

"Jam in print paper path. Open rear door and clear jam."

I have cleaned the printer and double checked all wiring to make sure nothing is broken disconnected anyone have any idea what to look at next?

Firmware has been updated recently to 20210408

[PSSG]

Remove paper from cassette tray and power up.  Same jam message?  Power off printer and  switch paper to the manual tray.  Power up printer.  Does display look like normal boot up process?  Do you hear normal motor and belt movement?  Same error message?  Paper sensors are attached to the pick up assembly, RM1-8045-050CN.  Other paper sensors are attached to the fusing unit, RM1-8061-000CN.

[rezz1777]

"Remove paper from cassette tray and power up.  Same jam message?  Power off printer and  switch paper to the manual tray.  Power up printer.  Does display look like normal boot up process?  Do you hear normal motor and belt movement?  Same error message?  Paper sensors are attached to the pick up assembly, RM1-8045-050CN.  Other paper sensors are attached to the fusing unit, RM1-8061-000CN."

- There is NO paper Jam

- When printer is powered up the printer goes through cycling and once it gets to the fuser the fuser gears click a few times and then paper jam error message come on screen.

The gear with the red arrow has teeth behind it that drive the gear on the other side and that gear drives the fuser. However when the machine first starts up those two gears just click and throw the jam error. If you turn the gears counter clockwise they all drive fine. However if you turn the gears clockwise they skip/click. It is almost like the motor is spinning in the wrong direction. 

I inspected the gears while I had it apart and none of the gears look like they are worn. I have no idea what direction the motor is supposed to spin. So I do not know if the problem lies in the motor or the gears. 

I replaced the fuser with a brand new one and that did not do anything. 

[PSSG]

Thank you for the detailed update.  I know how frustrating this issue can be.  Rotating the fuser gear by hand, I think that the fuser gear has to turn clockwise in order to feed the paper correctly to the output.  To turn the fuser gear clockwise, the fuser motor drive gears rotate in the counter clockwise direction.  If the printer cycles through the belt rotation on start up, then your main drive is turning.  It sounds like the DC controller is sensing a paper path jam.  This is a bug hunt.  The jam error occurs when the printer evaluates the paper path.  You have eliminated the fuser.  That leaves the pick up assembly, DC controller, or fuser motor.  I have worked on a lot of these color printers with the toner tray set up.  Double check your pick up assembly sensors and roller.  Make sure all are in the proper place.  If you have the skill set, you can remove the fuser motor and safely position it away from the printer to see if the motor turns.  I think that printer system is designed to stop motor drive process if resistance is encountered.  Removing the motor will allow verification of motor movement.  I have never replaced the fuser drive gears.  If mechanical inspection and troubleshooting fail to identify the cause, the DC controller would be the next possible cause.  I have had a couple of these type color printers that had to be replaced.  Good luck.