Make sure you have the radio code. Then, disconnect the battery for like 10 minutes. Reconnect and drive. See if the codes come back.

If the car drives fine and your tranny fluid is red and smells fine you should be OK.

On my V6, I had an electrical problem that triggered the tranny to not work right. D4 was flashing. I just fixed that electrical problem and reset the ECU by disconnecting the batt and the problem went away.