The inner speed sensor if not reading could cause this. Sorry abou the pic I forgot to post it but will now. This is definitely a trans problem or electrical. It may be the can bus is messed up which a pro will have to look at with his scanner to see. But the tcm has set the 1529 code so it gets straightened out then it may be able to be erased and fixed.
Images (Click to enlarge)
Monday, November 16th, 2015 AT 7:00 AM