No communication with ecm-Cutlass

Working on a 93 olds cutlass supreme 3.1 vin t. Can not communicate with ecm through snapon fasttracker scanner. The scanner works on other vehicles, so it is good. The car would not relearn idle after several tries. We have followed the diagnostics tree using Alldata many times to make sure it was correctly diagnosed, and replaced the ecm. I am on the second ecm and cannot communicate at all. The only thing that we have done is, disconnect neg. battery cable, unplug ecm, connect new ecm, reconnect cable and try to run diagnostics, but the scanner does not recognize any signal. Have checked all fuses and all wires from dlc to ecm connector for shorts and opens, also for good ground. Can anybody help me?


Thanks

Working on a 93 olds cutlass supreme 3.1 vin t. Can not communicate with ecm through snapon fasttracker scanner. The scanner works on other vehicles, so it is good. The car would not relearn idle after several tries. We have followed the diagnostics tree using Alldata many times to make sure it was correctly diagnosed, and replaced the ecm. I am on the second ecm and cannot communicate at all. The only thing that we have done is, disconnect neg. battery cable, unplug ecm, connect new ecm, reconnect cable and try to run diagnostics, but the scanner does not recognize any signal. Have checked all fuses and all wires from dlc to ecm connector for shorts and opens, also for good ground. Can anybody help me?


Thanks
Welcome to AF. Does it power up, if not look at the liter fuse, if it does and says no comm, trace the comm wires back to the ecm look for an open circuit.

Will double check fuse, and wires to ecm. The thing that puzzles me is, I could view codes and data with the original ecm. Maybe a fuse could have been blown somehow during all of the tests, besides the one in my brain.

Thank you.

Or the new ecm is bad.