F99 displayed; oven controls may lock up or become unresponsive

Safety first: If the oven is heating and controls are unresponsive, turn off power at the breaker.

• Check control lock:
  • On many Frigidaire Professional models, press and hold the Lock or Control Lock key for 3–5 seconds to toggle the lock.
• Power reset:
  • Turn off power for 5 minutes, then restore and test.
• Inspect keypad:
  • If certain buttons feel stuck or do not click, the touchpad may be failing.
  • Remove the control panel cover and inspect the keypad membrane and ribbon cable.
  • Replace the control panel / touchpad assembly if defective.