With the Jumbotron display on-press and hold the top button on the handle bar remote(not the up/down toggle).
Use the down button and go to settings-then calibration, use the the top button to select-follow instructions.
You can change your tune as well in these menu settings.
Hope it helps.
Have you tried to re calibrate from the menu in the Jumbotron display? Other than that you might need to go to the LBS. Check that your three sensor magnets are still there on the back wheel as well.