Hi all, I replaced de engine in my 2012 JK with a 2013 after an overheat. Everyhing went ok when installing the new engine. It turned on ok with no problems, but when trying to shift gears it wont move. I towed it with Transfer case in neutral and parking when it overheated. I verified that the linkage and bushings are ok, and that everything mechanical is moving as i shift. I tried with the Flashpaq that i have for it and it askes me if it is the same unit as before and when i answer yes, it says to ask customer support. Cannot read codes or anything. I used an Autel ML629 and it throws 4 codes: u1400, u1402, u1404, u140a. I removed the intake to verify for burned or broken cable and everyting looks ok. Also disconnected the pcm connectors and the tipm connectors and inspect them. I dont know what else to do, i think there is some wire broken but i dont know where to look. Any help would be apreciated. Thanks

 

U codes are all related to the Can Bus communication system. Can't advise any further other than look them up on the internet. There are pretty good descriptions there.

 

Those codes seam to indicate a possible loss of communication with the TCM. You either left something unplugged, or damaged some wiring somewhere would be my guess. Check around the back of the motor, firewall, transmission. Also, double check all of your grounds. Leave one off, and all kinds of funky stuff happens.