This won't help much; need to get the car scanned for OBD codes and then start troubleshooting from there.
Mine did this for a while that started when I abruptly put in in reverse too quickly and aggressively for the transmission that made a noise when I did it, It was very annoying to watch the blinking 'D' and 'R'. I found a post that fixed it and copied and it worked. You have to disconnected the battery to for about 30 minutes, I believe. It did not clear the learning disconnecting the battery in Park. I put it in gear. Turned motor off then disconnected the battery for more than 30 minutes. You get 'bars' on the dash instead of letters. Then go into the learn mode. That fixed mine (on my 2011 - I also have a 2015 - a trivia fact - the 2015 hood latch mechanism is different- I like the 2011 better - you might need a thin screwdriver with the 2015). Obviously, use caution on anything I did, not being a Smart Car technician.2012 smart car 23,000 miles...When I put it in reverse or drive the letter flashes but the car drives fine. Also it shows the wrenches flashing. I tried to reset service ( wrenches ) it put the mileage to 10,000 but wrenches still flash. I have noticed a little smell like burning rubber sometimes when I park it and get out. Any ideas?