Pretty sure I fried my ECM

My original issue was oil pressure would drop on gauge when engine got to operating temperature, the check gauges light would come on but only when at operating temp. I replaced the sending unit the gauge stayed up longer but after a while it would drop again, before testing with a mechanical gauge I checked power and ground with my power probe at operating temp while the engine was running. For all I was getting was ground from two wires and nothing from the third so "thinking " it was a good idea to see is I can get the oil gauge to move I applied power to the said wire and the engine died. Now I have no communication with my scanner, my fuel gauge reads empty (it's at 3/4) and my battery gauge reads below 9v. I don't want to start throwing parts at this