An "F" error code indicated a problem with the chair.
Sample Error Codes F03, F04, F05, F06, F08, F11, F12, F14, F15, F16, F17, F18, F33, F34, F34, F36, F37, F38, F73, F74, F75, F76, F80, F81, F82
This answer is for the following models EP-MA03, EP-MA10, EP-MA70, EP-MA73, EP-MAG3, EP-MAJ7, EP-MAK1