P 1684 is "Battery disconnected within last 50 starts"
In the 1998 Intrepid ES, 1684 indicates a problem with the catalytic converter. It probably is the same for the 2000.
Trouble code P1684 means:The battery has been disconnected within the last 50 starts
1684 The battery has been disconnected within the last 50 starts
P 1684 code refers to your battery being disconnected (it should go away on its own after about 25 physical restarts as long as you keep the battery connected). The P 1299 is a manifold pressure error. Listen for leaks (hissing sound under hood) and look to see if any hoses are loose or disconnected.
The 1684 code shows a lack of power to the transmission. Check the wiring to the transmission for damage, and worn or improperly connected plugs.
Probably means battery disconnected or discharged within the last 50 starts.
P1684....Battery disconnected during last 50 starts
Trouble code P1684 means:The battery has been disconnected within the last 50 starts
Cylinder Deactivation System
what year is your car
1684
it a transmission slipping code