My engine does no start

Hello everyone, I need help please. when I put the key in the start position I have a lot of fault on the dashboard, in branch the diagnostic case the mechanic to note that the engine calculator is not found. he made a shunt on a relay and the case could see the calculator which allowed him to erase the defects. after removing the shunt we tried to start but without success, the starter does not even turn (it is good condition). when he puts the shunt we get to start but the engine speed is catastrophic and the vehicle has no power and we can not even accelerate. The relays and fuses have been controlled and are all okay. the defects come back and not moment one that indicates error engine calculator. Help me please.