A collection of diagnostic and troubleshooting information associated with a power driven wheelchair is stored for access by a microcontroller to be displayed to a user to assist in troubleshooting the power driven wheelchair. A log of fault codes transmitted by various fault-detecting mechanisms is compiled. A user may request display of diagnostic information associated with a selected fault code.The operating instructions of a power driven wheelchair may be updated by using portable storage media onto which a latest version of operating instructions is loaded to transfer the updated operating instructions to wheelchair controller memory.The calibration of a power driven wheelchair can be simplified by providing functionality within the wheelchair controller to change calibration parameters or to transfer calibration parameters from portable storage media.