[Dave Z]

Did you try jiggling the rheostat a little when it happens? Our 300M has been doing this for years at random intervals. It really needs a new headlight switch/rheostat. I figure either there's a little dirt or a little corrosion in there.

Probably should replace it. The one in my wife's Escort started to smoke at 30,000 miles. The 300M's well over 100.

 

[ImperialCrown]

There probably is a fault code stored in the WCM if there is a key transponder fault. It could very well be SKIM key related.
They could also scan the CCN (cluster) and BCM for faults that are turning on the security lamp.

 

[AllanC]

We have been using an alternate key fob with built in remote. This unit is newer and has a fresh battery. The security lamp does not blink intermittently. I believe the intermittent blinking was caused by the system sensing a low battery in the remote and flashing the lamp as a signal. I did not have the system scanned for a diagnostic code. It seems silly to pay $75 - $100 in diagnostic fee to just be told a $4 battery in the keyless remote needs to be replaced.

 

[ImperialCrown]

That could very well be. There are fault codes for RKE low battery. I know that a TSB was released in the past also that other transponders on your key ring (eg: Mobil Speedpass) in close proximity to the ign cylinder SKIM antenna could also set false codes and interfere with starting the car.

 

[DiGiTaL D]

My wife's '08 Sebring just started doing this. So far the engine hasn't shut off by itself. Funny thing is we got a brand new OEM key made by the Chrysler dealership about a year and a half ago after wifey flushed her original one down the toilet (whole other story). The remote lock and unlock functions of the key itself seem to work fine. Is this more likely a weak battery in the key or something on board? No trouble codes stored, but I don't have a Star Scan laying around, so...

 

[ImperialCrown]

The problem may not be in the key. I believe that the fob battery just powers the lock/unlock transmitter. The security ID chip transponder for starting may be independent and passive and not require a battery for operation. A loop antenna in the column 'powers up' the chip inductively to read the ID.
Most fault codes for SKIM won't show on the EVIC or an OBDII code reader. Most readers only read PCM faults. You need a more specialized scan tool to read other modules,