Wait for the self-cleaning cycle to finish. This may take up to one hour or more. Use an oven mitt to slide the manual lock from left to right.
Turn off the oven by touching or pressing the "Off" switch. Turn off the circuit breaker that feeds electricity to the oven. Allow the oven to sit undisturbed for five minutes before turning the power to the circuit breaker and oven back on. Open the door.
Unplug and slide the oven away from the wall. Remove the top panel of the oven and access the locking mechanism. Slide the lock open from the inside of the panel. Return the top panel and push the oven back into place. Plug the oven back into the wall.
Read the error code displayed on the oven's console. Call a Jenn-Air repair person to determine the issue affecting the lock.