[ImperialCrown]

Welcome back! Don't disconnect the battery until the codes are read as it will erase them.
Disconnecting the battery comes last or you can wait until the repair self-erases the code (in about 3 trips).
Here is a link to the original discussion:
http://www.allpar.com/forums/topic/143381-mystery-car-cant-be-fixed-1989-dodge-aires/