Hyundai Repair: 2001 Hyundai Sonata, hyundai sonata, output speed

Question
I was driving my car yesterday and it just changed gears VERY hard as I can to a red light, causing the check engine light to appear. As I left the stop light the car was moving very slowly until it reached the speed of 20 then it drove like normal. I park to go into the store and when I came out to go home the car drove fine. With the check engine light still on I went to Auto Zone to get a reading and the codes were P1529 and P0720, and of course the Auto Zone couldn't read what that meant, any help??

Answer
Hi, Dawna.  P0720 indicates there is a problem with the signal from the transmission's output speed sensor.  P1529 simply indicates that the transmission control module (TCM) requested that the engine control module (ECM) turn on the check engine lamp.  

Although there have been a few exceptions, almost every time I've seen the P0720 code, the problem has been with the output speed sensor itself.  The chances are large enough that this is your problem that I'd recommend simply replacing the sensor without further diagnosis, and attempt diagnosis later only if that doesn't fix the issue.