Chrysler Repair: Computer codes on 95 LeBaron: code 12/trans codes?, chrysler lebaron, drb ii

Question
I have a Chrysler lebaron 1995 not shifting quite right (hunting at 40-45 mph. I pulled the codes and 12 and 17 came up. 17 was temp to cool changed thermostat and it was weak.  Cleared codes and 12 continues to return. is this a problem.

Answer
Hi Mike,
The 12 code is often a false positive. It means that the battery supply to the computer was disconnected sometime in the past 50-100 key cycles. It could mean that the clamps on the battery post are loose or corroded, so check that. Otherwise I wouldn't worry about that code.
On the trans not shifting quite right, the trans controller fault codes are accessed thru the plug at the left end of the dash behind the fuse door. It can't be read with the ignition key but rather requires a Chrysler Diagnostic Readout Box (DRB II). Let me know what codes you get from that if you do it, and of course we can compare that with what the shop who does the readout says. But only the data link connector plug will get to the trans controller.
Roland