Robot won't stop running!!!

I am having a huge problem. Whenever I turn on the cortex the robot’s drive will constantly run. We put the competition switch on the controller to see if it will run. When switched to driver it will run and when switched to autonomous it will run even though there is no autonomous. This seemed to happen right after we added our quadratic shaft encoder and potentiometer. I believe that it has something to do with the program, but I am not completely sure. If you can please help that would be great! Thanks!

Without seeing the program it’s hard to help.
perhaps at least verify the code is the problem by running something very simple that does not start the motors.