Repeating ADF Jam Message For HP Officejet Pro 8620

[RKO1]

You may have to follow the ADF wires going all the way into the control panel.  Maybe there's another harness that's loose. Try removing the left side panel of the printer to access the wires and harnesses in there. 

[DennisFG]

RK01 helped me save a brand new (sitting in the box unopened for 4 years) printer from the scrap heap! When I read this the first time, I found some comments about opening access to get to the left-hand (looking from the front) motherboard. I didn't read RK1's message closely enough. If you pivot open the ADF cover (which you would have to do if the feeder is really jammed), along the BACK of the printer, very close to the lip of the cover. See the first photo below. I've included some of the printer itself to orient you correctly. The blue arrow points to the black Torx screw, just as RK01 instructed. So you will need a small Torx screwdriver. RK01 said T8 but mine needed a T10.

Now that you know you've found the right screw, unscrew it.

In the second photo (again with some context to orient you), one of the wire connections was loose. Just probe around on the wires to see the connectors. In my case a junction between two white wire ends was a tiny bit loose. The wires looked connected but they came apart "too easily." After pushing them together firmly, they clicked. Then when I tried to pull them apart again, they were harder to separate. Push together firmly and before putting on the cover, turn on the printer and see if you can did it! Then if you still get the message you can try again. If successful, you will finally be free of the pesky ADF message!

The cover is not very easy to put on again. Just be patient and gentle. Keep trying and you will eventually find how it fits.

The blue arrow points to the Torx screw to remove.Here it is with the cover removed.

[DRamirez1]

I was having the same issue. One day it was working the next day I kept getting ADF jammed even though there was no jam.

I was able to clear up the problem by cleaning the rollers. They get dusty and the feeder is not able to grip the documents. I used a damp free wrag and left the ADF door open so they could dry for 10 min.

It worked!!!