2 no bus codes p0700- no start

Hey so here's my story. I had to replace my ecu earlier in the week due to no charge function and no communication with my pocket scanner as well as with a Matco scanner. I replaced the ecu and gained all dash function back as well as communication with my ecu. My issue now is no bus no communication. I can still read the 3 codes with my scanner but not erase them. I do have injector pulse. The guages work perfect. The no bus is not lighted on the dash. I don't even see the light for it even it was to trigger. The 3 communication codes does not trigger the light. The light only triggers when I pull a sensor. If I were to leave the airbag to the steering wheel disconnected would this trigger this code? The new ecu is a salvage ecu from the same year Heep. Vehicle is a 97 country. Thanks.