We have a 2014 Chevy Equinox we replaced the engine. It drove after installation for a few miles. It then just died or lost power and coasted to a stop. It then did not turn over - no start no crank. It is not the battery or starter. The starter is not getting the signal to start. I do not think it is the neutral switch, ignition switch. Using the code reader I rented it cannot connect with the computer or communicate. Is it the computer isn't compatible with the motor? We do not have a check engine light in 3rd position which may interfere with connection. I checked all the fuses as well. Where could the problem lie?

if any sensor or wiring from computer to sensor shorts out, you will get no communication. Pray it's that and not a shot computer or the wrong one for that engine