Have you tried clearing the code to see if it comes back? If it does, there is an issue with the ECM. Look for any loose connections. If that isn't it, you may have to reprogram or replace the ECM.
J
You are most likely correct. However, i would feel kinda dumb if I bought a new ECM when it was only a corroded connector, a loose wire, or it could have been reprogrammed. Start with the simple inexpensive stuff first. You might get lucky. If not, at least you know how the system works.