stuck in 1st gear

[tundraathome]

i am currently working on a 2004 dodge neon that my neighbour said was shifting fine[auto] but when pulling away it refused to shift out of 1st gear. i pulled the codes p0720 and p0715 indicating sensors, disconnected the battery ,erased the codes but on a whim put the battery back in ,took it for a drive and everything was shifting normally. it definately was refusing to shift as i drove it myself. i am not a big believer in things fixing themselvesso any adevice is appreciated.. p.s. there was also another code p1684 [battery discnnect] but it has not been unhooked for years sam