Q: One time dtc for ecm staying on when car is off.

Got in my car, battery was dead. I jumped it, ran fine. Got to work, turned it off, end of day battery was dead again. Sometimes its completely dead, sometimes there's still a little juice. Its been 2 weeks or so its been like this.

Dtc for ecm staying on while ignition off came on one time, never came back. But still killing my battery. Did some digging, positive battery terminal was loose, I tightened it. Seemed at first that it was keeping a charge. But still in the morning it turns over real slow.

I've heard random bad relays could cause it, bad grounding, or just the ecm dying. But the only thing its causing is my battery dying. I've checked the grounds I could see and they are all tight, free of corrosion.

Any suggestions?

My car has 70000 miles.
My car has a manual transmission.