I have Diagnostic codes P0700 & P0740 wont pass emissions test.

Sometimes low transmission fluid or the wrong fluid can cause the P0740 Torque Converter Clutch circuit code. Was the transmission fluid changed recently? It needs to have ATF +4 fluid and the proper amount. If the fluid is not the issue, then you have a problem in the torque converter. If you need to get through emissions, get a bottle of black lubeguard (a transmission fluid additive) from an auto parts store and add that to your transmission fluid. Then have the codes cleared and drive the van over the weekend. If the check engine light doesn't come back on, chances are good that the emissions monitors have reset and it will pass your emissions test. If you have an OBD II code reader you don't have to guess when it's ready, but a weekend of driving should do it. This is not a permanent fix, but it might get you 6 months or more. I would also have a chat with your transmission guy. It's probably out of warranty, but with such low miles they might be able to just replace the torque converter if you want to keep the vehicle.