Unable to print 4F

"I fixed my MFC-J615W by merely opening it up and jiggling the head left and right a few times. It is possible that I just needed to unplug it for a few minutes for error to clear. Hoping (and expecting) that I can run a few more reams of paper thru it before replacement.

Extremely disappointed with Brother Support. Screen says refer to troubleshooting in User Manual - downloaded - nothing at all about 4F error code. 15 minute call with Brother Support, only thing they could tell me is ‘take to service shop’ - they could not tell what 4F meant. Call their recommended service shop - $79 just to diagnose but cleaning and adjustment was no extra cost. Asked what replacement of HEAD would cost “the tech will quote after diagnosis”."