Engine Light On, No power

I've disconnected the negative post for approximately 20 mins, I'll try it for overnight and see what happens. Not sure exactly which strand the bad relay was but have since replaced with new relay, I have a Tune ECU on it's way, Thank you for your assistance
 
Ok, broke down and purchased the tune ECU kit and went through about two hours figuring it our and downloading everything drivers etc. The diagnoses came back with 2 codes first, PO560 ECM power supply circuit malfunction, Next was PO351 Ignition coil circuit malfunction. The first code cleared and did not return when running for about 5 minutes, the coil malfunction stayed.
Does this make sense to you? I believe that I damaged the coil and will have to replace.
 
Congrats Steve on finding the problem. You are now a certified R3Owners mechanic with practical experience in TuneECU. It's a great tool to have also for future troubleshooting and maintenance. Aren't you glad you now own it???