After change my control unit withe new one i have two fault p0170 Fuel Trim Malfunction (Bank 1) Malfunction U1602 - CAN Data Bus - communication error probable cause- what i can do ?

Had U1602 fault when replaced 8v engine with 16v. And ecu, of course. Fixed in two minutes with "Launch", there is an option to rewrite Fiat code.

After 5 day the yellow motor dashboard still refresh and still have p0170 how to write fiat code

thanks for help
I made ecu learn by let the motor car temperature reach 90c then raised rpm from ideal to reached 6000 rev and repeat it 3 times then switch off car and wait 10 second and switch on there is no error and at last my car back to normal
thanks for support