D lights flashed when I was driving long distance (coincidentally, at the same exact time the fuel cap blew setting off the check engine light). Turns out it wasn't a code, but the light going out to match other dashboard light outages I've had on the car from the beginning. I opted not to spend hundreds of dollars to fix this since I can tell if the car is in drive with my own eyes. The other letters did not go out. I would have had to pay $102.50 for the diagnostic, but that went towards the fuel cap, I guess.