Don't worry about A3 codes but 322 is incorrect gear ratio (I believe, from memory) and it's most likely a bad PNP switch. Clear the code, move the shifter though the gear selector and see if it re-occurs. Sometimes when the PNP switch is starting to go, you'll get the code, flashing arrow after shifting into D1 when that's normally rarely (if ever) done.
The 322 code could also mean bad S1, S2 solenoids mounted to the valve body too but I'd start with a PNP switch first as it's easier, cheaper and more likely. 313 is a definate PNP switch but 322 can also occur with that as well.