As you've identified P0700 is a Trans control module issue that can be caused by faulty wiring but also by a faulty
TCM or an issue with the transmission itself.
The P068a was probably caused when you checked the relays. If you power cycle the
PCM normally (start engine, turn off and remove key from ignition) the DTC will probably disappear. If not let us know.
Not quite sure where you go for the P0700 - you'll need to actually read what codes are being thrown by the
TCM which not all code readers can do.