ghinson, I don't know for sure if replacing the BCM will resolve the error you've described. Often, an error code which seems to point to a faulty BCM can be triggered by a bad sensor or other component. Correct diagnosis of onboard computer devices can be very difficult without sophisticated test equipment and a full explanation of error codes.
Complicating this particular case is the fact that I don't even know the year of your Caravan.
However, I'm going to assume that you've misidentified the part that you disconnected, temporarily clearing the error. If it was under the hood on the left fender, it is almost certainly the Electronic Control Unit or ECU, not the BCM (Body Control Module).
This is consistent with the actions and result that you have described. Disconnecting the ECU had the effect of clearing any stored error messages. Upon reconnection, the fault, ostensibly a failure of the BCM to respond correctly to the ECU, returned and was stored again.
If you would like to try swapping out your BCM in an attempt to resolve the problem, you should be able to see the catch code without too much trouble. Look under the left side of the dash for an aluminum box roughly the size of your hand with fingers outstretched. There should be a number of plastic connectors each bearing a group of wires connected to it. You should be able to find the catch code with firmware revision in black on a white paper sticker.
Remember to disconnect the battery before attempting to disconnect or reconnect any onboard computer devices.
Good luck! Carl