Chrysler Repair: 99 Chrysler 300m: code 1684. engine dies.

Question
Hi Roland...we tried your suggestion copied and pasted below...the result is P 1684

(ANSWER: Hi Janie and Gery,
There are a number of possibilities but begin by asking the engine controller whether it noticed any cause and gave it a fault code number which is stored in its memory. Turn the ignition switch: "on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the odometer window to see if the mileage reading is replaced by a 4-digit number preceded by a P. Let me know and we'll go from there.
Roland)

Answer
Hi Janie,
That code is common and indicates that the battery voltage to the powertrain control module was disconnected some time in the past 50-100 starts. If you don't recall removing the battery clamps within that time frame then it would suggest that either a clamp at the battery or one of the wires connected to the - post battery clamp is loose at its far end where it attaches to the body or to the engine. Were there no purposely disconnects at the battery, I would loosen and remove the - post clamp and then trace along its wires to their far ends to verify clean tight connections. Then check the + post clamp on the battery to be sure it is tight. Then finally reattach the - post clamp to the battery.
If the battery was purposely detached in the past 50-100 starts, then that would explain that code and not be the cause of the engine dying.
Most causes of dying will set a code. The only item that causes that is a problem with the fuel/air mixture that is caused by the exhaust gas recirculation valve being gummed up which causes it to stick ajar when the engine is shut off or you slow to a stop and then the engine dies. To check that in your situation requires removal of the piping that connects to the valve and then the valve itself, and then cleaning out the passageways and the valve head and stem with solvent. I would not get into that unless this is persistent and no other codes show up other than 1684. By the way, the 1684 will be 'refreshed' by disconnecting the battery so it will be there until 50-100 future key starts have been done, then disappear on it own.
Roland