1389 means the automatic shutdown (ASD) relay isn't turning on.
320 means no signal from typically the crankshaft position sensor. That signal is needed for the Engine Computer to know when to turn on the ASD relay. Could also be related to the camshaft position sensor.
Can't find any reference to 1684.
July, 26, 2011 AT 8:40 PM
1684 is "battery has been disconnected in last 50 starts"
July, 26, 2011 AT 8:51 PM
Thanks Wrenchtech. Found it now in a service manual but not on our list. Boy, paper books sure are nice.