97 grand voyager codes - several

I have had this van for 3.5 years now and have replaced the engine once and the transmissions twice. It seems that the transmission is messed up yet again. I took it to a shop and he told me the torque convertor may have broke apart and the first front clutch. I hate to pay for another tranny unless I have to. We changed the filter and its shifting better but still not going well. I got the codes today but I don't know what they mean. Does anyone know what codes 12, 11, 13 and 16 are??? Please help.
Also, the van has never passed emissions beacuse of the code for leak detection pump. We replaced it but could never get rid of the code. Even after resetting. Any ideas?
Thanks for any responses ...
Desperate in Douglasville, GA

Take your van to an Autozone or Advance and have them scan the computer for you. The codes you gave are from the cel and only give basic information. If you have the OBDII codes that will help us give you better direction on what to do to repair the van.