It's not that simple. The ecm has 5 separate power feeds, and 4 grounds plus an ignition input. You just don't run a new wire to it. Spicing into the harness is not recommended unless absolutely needed. Your engine could be shutting down due to loss of ignition or battery power or something else. Those codes are not from the engine, but from the body controller reporting loss of communication with the engine. The main engine power feed comes from the mega fuses at the firewall. Tucked in the wiring around the air cleaner is a 25 or 30 amp fuse for the ecm. Check it for corrosion. Run the engine and wiggle the wiring gently to see if you can induce the problem to hopefully find a bad spot in the wiring. Engine ignition feed fuse is 5 amp and located in the fuse/breaker panel in front of the passenger seat. Give it wiggle too.