Es shifting problem

Hi there. I'm new to the forum and new to atv's in general. I just had a couple questions for anyone with experience. I have a 2013 foreman 500 with Es. It stopped shifting entirely and was stuck in first gear. Fresh oil, battery seems good. We took it to a mechanic and he cleaned the shift motor. Now it shifts but flashes a bar between gears and sometimes I have to try 3 times before it will up or downshift between 2, 3,4 or 5 gear. The gear no longer flashes, just a bar. Could it be the angle sensor or? I'd appreciate any feedback.
Thanks!