Help DTC code 0706
 

I have a 2001 S4 Tiptronic,and I am having a transmission problem. I scanned the tranny and I am getting code P0706 Transm.Range Sensor Circ Range/Performance. The code causes the Tranny to go into limp mode.
Can anyone tell me what that consists of? and what needs to be done in order to fix it?

note: When ever I clearout the code the tranny goes back to normal and it shift completely normal

thanks in advance