Our 2001 Dodge Durango stopped running after taking off the battery terminal and putting it back on can anyone help?

We've been using our Dodge Durango for a little over a month, but after taking the battery terminal off and back on again it would start but would only stay running no longer than 2 seconds before it stops again. We've tried scanning the car for problems using an autel car scanner, but all that came up was battery failure and problems about the PCM

the battery is new so do we just change the ECU/PCM??

hope someone can help

Is security light flashing? Take the battery to any auto parts store for a load test.