Best guess: replace the thermistor-the water temperature sensor. Try a cold water only wash and see if that works. If it does, then the thermistor is probably it.
Does the lid lock? Also Could be the motor. Also could be the actuator that shifts transmission from agitate to spin. Also could be belt issue. Or maybe something wedged between inner and outer tubs. Call a professional unless you’re comfortable with checking all this out.
LO or FL error is displayed if no water is entering the washer. Check to see if water valves are turned on and check in line filter screens at inlet to hoses. " https://www.6ya.com/callphilipforhelp
A similar inquiry has been previously posted, Hopefully one of the responses will relate directly to your low agitator speed problem -
Amana washer LWA50AW