DIAGNOSIS: Error E-04 is a motor hall sensor fault. The controller is not receiving the correct positional signals from the motor.
FIX: 1. Turn the scooter completely off. 2. Inspect the three-phase motor wire connector where it plugs into the deck near the rear wheel. Disconnect and firmly reconnect it. 3. Check the thin sensor wire connector (smaller, multi-pin) in the same area and ensure it is secure. 4. Power the scooter back on.
IF THAT DIDN'T WORK: The fault may be internal to the motor or the controller. A persistent E-04 after checking all connections typically requires professional diagnosis or a replacement controller/motor.
HEADS UP: Do not attempt to ride the scooter with an E-04 error, as motor operation will be erratic and may cause a sudden loss of power or jerking.