I have a March 2015 BBSO2 500 watt installed with 150 trouble free miles until yesterday. I was out for the first ride of 2016 (been on my trike) and almost immediately started getting error 30 code with the motor cutting in and out on PAS1 and display numbers dropping to zero and back to normal display of speed. I checked out all wiring and spedo connection, shut it down and restarted and still happening. Error 30 is a nondescript communications error. Battery fully charged with 55 v. on my multimeter. Now the display will not power on at all. The vendor selling me the unit says it is most likely the controller. Another well respected expert on Bafang says it is the display. I don't know if the display will power on with a bad controller, but I know the unit will not function with a bad display. Do any of you have any advice or experience with error 30 and controller/display issues?