Need ecm help in Hilton Head, SC

[Hilltop]

Hey guys, on vacation with wife in HH, SC in my Roadmaster Wagon. I had a check engine light and car started running bad. I pulled over, checked codes with my OTC 4000 scanner…it had multiple codes whereas it previously had none. All indications are pointing towards a bad ecm or maybe a bad ground…wiring and grounds appears fine. My question is, can I put a salvage Yard ecm in it or will the GM PASSKEY prevent the replaced ecm from operating? I found an ecm 75 miles away, I can rent a car at the airport and drive out to get it but not sure if the car will even start with it. The car is running and driving now but the codes keep coming back after clearing…too many codes to be legit. I installed recent good quality Optispark, etc…this is a real nice, well maintained wagon that I have put about 50 hours drive time over multiple states in the past 30 days. If anyone happens to be in the Hilton Head area and can offer any advice, it would be most appreciated. Just trying to get medically challenged wife home safe.

thanks, G