Here is what I have came up with on my dozer
-its a 2000 model john deere 650H LT with a cab and ripper
-it first started veering to the right when tracking straight then it completely quit turning left, i tried too re-calibrate but it started throwing codes and everytime i got to left steer it wouldnt recognize that i was moving joystick.
-I bought a new speed sensor for $160 and tried it in all 3 places. pump speed, left drive, right drive. still same thing, would not recognize left steer.
-I then called out local mechanic to plug computer into transmission controller, well he showed up without computer and said he can do it without it. well $580 later he says he has no clue whats going on and then decides to tell me he only works on CAT
-next I went ahead and bought the overpriced $380 left and right steer sensor. disconnected batteries overnight.and then installed the new potentiometer, hooked battery back up and calibrated. everything went good and it got me through calibration
-drove dozer around and it was tracking and steering great. parked it and turned off to re-install floor board and put armrests back on
-started back up and now it is throwing F340 (B5 left and right steer sensor, open circuit,shorted circuit,or no feedback is indicated) and will not steer at all and will not let me re-calibrate
-Any ideas or theorys would be greatly appreciated, ive been down for 3 weeks and got a lot of money tied up in a still occuring problem