have you replaced the pcm on this vehicle by any chance, if you did, the replacement pcm will not communicate with the old/original  immobilizer, you have to replace the immobilizer as well to gain communication again. btw  today i tried a 2001 mitsubishi montero and there was no immobilizer special function at all for this vehicle, only code read, erase and data that is it.  i had to used the mut3. anyway as i was saying back to your issue. if you did not replace the pcm/ecu make sure all voltage and ground are present at your immobilizer and pcm, you will need to be looking at a wiring diagram. 2 questions is your sel light on and is the security light coming on?. also i had to used a new immo on mine, was not able to program a used one.

 good analysis. let me ask you something did your software had the special function on immobilizer for this vehicle, as far as pin read and the programming of the key?

  had to remove it locksmith are getting pissed

 had to remove it locksmith are getting pissed.

  this morning i had to do another mitsubishi and was not able to program anything do to functions not available. what i ended up doing since my mut3 wouldn't work today was  going to a junk yard and getting the pcm,immo,ign cylinder and key and got that junk solved. autel needs to develop this make, I have no time to be visiting this junk yards and all this extra work.