Do you have the superword?
Self test is checking all the devices and communications between the unit controllers. You will need to read the codes on the controllers as it goes through self test. It could be something so simple as a bad or out of adjustment foot pedal switch, to a blown fuse to a bad vehicle or carriage manager.
This is ONLY to be used to report flooding, spam, advertising and problematic (harassing, abusive or crude) posts.