I have a 1998 Cherokee that is giving me a check engine light.  The code for the light is 0700 - Transmission Fault.  The tranny shop says there is nothing wrong with the transmission.  They say the transmission computer does not want to talk nice the the main engine computer.  (I've tried grounding the computer for not playing nice...but that didn't work)  There is something in the network that seems to be causing problems.   Perhaps a loose wire...but I don't have a clue where to start looking.  The biggest problem is that I can't get the thing to pass smog until the problem its fixed.  Any suggestions? 

pick up a service manual  

if the 0700 code is the only one that shows try swapping out the tranny computer that should fix your problem the computer new from the dealer will run you about 700 try to find a shop that has them rebuilt rebuilts run around 300- 450 then have them flashed if they need it by the dealer or the shop