p1684 code

P1684 is only a status which indicates that the PCM memory has been cleared within the last 50 ignition cycles and does not indicate a problem, so someone cleared the memory or the battery went dead. in the event the battery went dead, the computer likely forgot the iac valve (idle air control) position which is extremely common in dodge systems. Try starting car at part throttle, if it starts drive car without letting it idle for a short time, the computer should relearn iac. If this helps then you'll need to find out why battery died. Good luck!