Amana ovens, like many others, have a built-in locking lever that is used when setting the oven to its self-cleaning setting. The ovens have an internal sensor that keeps the locking mechanism locked until the cleaning cycle is complete. An oven that never completed the self-cleaning cycle may appear to have its lock stuck leading to an erroneous idea that the mechanism itself is faulty.
Consult your Amana oven owner's manual or instruction manual about the self-cleaning function of your oven. At this point, you can choose to allow the oven to complete its self-cleaning cycle, which will permit release of the locking lever when finished, or you may proceed to the following steps.
Turn off all dials of the oven and unplug the unit. Alternatively, turn off the circuit breaker switch connected to the outlet being used for the oven. Keep power removed from the oven for about five minutes.
Before restoring power to the oven, try to unlock the oven by sliding the lever in the direction necessary to unlock, according to your oven owner's manual. If it unlocks, restore power to the oven. If it doesn't unlock, restore power to the oven and try once again to unlock the oven. If you are still unable to unlock the oven after following all of these steps, consult a certified Amana technician as the locking mechanism contains no user repairable components.