2000 Dodge Neon P1684 Error Code: Battery Disconnection After 50 Starts

I've searched the forums extensively and found helpful information, but I still have a few unanswered questions about my 2000 Dodge Neon. The P168-4 error code indicates that the battery was disconnected within the last 50 vehicle starts — which is accurate, as I previously left my lights on and ran down the old battery. After replacing the battery, the check engine light didn't come on initially. However, a few days later it activated. I then performed the standard 'on-off-on-off-on-off' sequence, which triggered the P1684 code. I've already disconnected the battery, cleaned the terminals thoroughly, and reconnected them. What should I do next to resolve this issue or clear the code permanently?