Hello, I have a 2006 f150 5.4, I recently aquired a trans fault message. Here's where the trouble begins, I was a Ford tech for 3 years out of wyotech so I have knowledge. I tried a snap on solus to retrieve the dtcs and the scanner wouldn't communicate. No problem, try a matco scanner same problem. No communication on any module, however a little reader will communicate to the ecm, and even run a self test. So I know that power is at the DLC. I started with checking fuses and connectors at ecm including pin fit and all is good. I checked for 60 ohms for terminating resistor and all is good. Checked continuity on high speed can bus from dlc to ecm and abs module all at 0.2 ohms. Checked ground strap on frame, cleaned and replaced with no difference. Ecm shows no codes and all monitors have run, on the cheap scan tool. But I cannot establish communication with any scan tool unless it's a small little reader or cheaper tool. Checked for tsbs before I even started with limited access and found nothing, truck runs and drives with a delay when stopping and slams into gear on takeoff periodically. Any insight or help as to why these scan tools won't connect would be greatly appreciated.