I have a 1993 Dodge Caravan with Code 12 - Battery or Computer Recently Disconnected. I need to pass E check, what can I do to help pass? Engine pings

To help you pass your E Check , Replace the Catalytic Converter , Fresh tank of the highest Octane gasoline you can get, Add a bottle of octane boost.( can be bought at about any auto parts store) let the car run, or drive it until it is at Normal operating temperature ( between 180 and 220 degrees ) . Take it to the e check place and let them do the test. This should give you a significant drop in readings and allow you to pass the test.

If your engine "pings" just once it will fail the test. The ping noise is pre- detonation which is caused by low octane(cheap gas) the Octane boost prevents this from occurring. The Catalytic Converter will bring down the Nox number dramatically. You don't have to drive it 20 miles  5 to 7 should do it. The purpose it to allow the catalytic converter to get up to functional temperature. It reaches 350 degrees. If it isn't warmed up it will not function properly.  Be sure to leave your car running while waiting in line .