Chrysler Repair: PCM readiness failure code 1684, pollution control systems, nc dmv

Question
My 96 Sebring Convert 2.5 L fails NC emissions due to lack of readiness codes. The car runs fine, but each time I turn off the ignition, the PCM sets a code 12 that indicates a battery removal event within the last 50 starts. Dealer flashed the latest firmware to no avail and now wants to replace the PCM for $900. I think the PCM is really doing what should be and telling us that it has lost power when the ignition has turned off. If so, a new PCM won't solve the problem. Without access to wiring schematics I can't track down possible wiring failures or connector failures. Am I all wet, or can you shed some light on how to determine if I am right.

Answer
Hi Robert,
That code is a "status indicator" not a "fault code" in the technical sense. The possibility is that there is a loose or cracked conducter (which spontaneously open and closes with usage) in the fuse that supplies the PCM full time which is number 5 in the power distribution center under the hood according to my '98 Sebring manual. That fuse is the only one that provides full-time power to the PDC. So take a look closely at that fuse. Then try cycling the ignition switch 50+ times to see if the code goes away or not. You could also put a voltmeter on the downstream side of the fuse to see if there is any indication for such an interruption in voltage. Remove the fuse and see which clip is "cold", then replace the fuse and monitor the voltage on that side.
The red/tan wire from the fuse goes through a 3-wire splice in the PDC and directly to pin 46 of the PMC so you could monitor that point as well using a pin to probe the conductor through the insulation. Finally, check the black/tan ground wire from the PCM at pin 50 to the left strut tower to be sure it isn't loose.  
My inclination if you can't find a reason would be to appeal to the NC DMV for a ruling on whether that code is in actuality a disqualifier as it does not impact the pollution control systems and is not techinically a fault code.