Communication Error
 

I have a '99 ex civic that was stock with a D16. I swapped the motor out for a B16b that came with its own computer so that everything should have been plug and play. Swapped the motor, installed the computer. I noticed after my thermostat opens up, my check engine light comes on. I went to plug my scanner in to read the code and it keeps coming up with "communication error" so I have no idea what code is causing the check engine light. Any help would be greatly appreciated!