DIAGNOSIS That is a general error code. It means the scooter's controller detected a fault. The most common cause is a brake sensor conflict.
FIX Power the scooter off. Pull and hold the rear brake lever. While holding it, power the scooter back on. Keep holding the lever for 5 seconds after the display lights up. Release it. The error should clear. If it does, turn the scooter off and on normally.
IF THAT DIDN'T WORK Check the brake lever return. It must snap back fully. If it's sticky or loose, it's sending a constant brake signal. Spray electrical contact cleaner into the lever mechanism at the hinge point. Work it in.
HEADS UP Do not ignore this error and try to ride. The scooter will cut motor power unexpectedly if it thinks the brakes are engaged.