Chrysler Repair: engine shuts off, probably due to alarm system?, obd scanner, odb2

Question
QUESTION: I just bought a 2001 Sebring Convertible and have problems with starting the engine. The engine runs for 2-3 seconds and then shuts down. This happens about 3 times, then i cannot restart the car for about 24 hours. After this time the engine starts and everything is OK, which is actually very strange because it makes it difficult to analyze the problem.
This happened already the third time to me, and , curiously, only when my colleague is with his car at work too. He has the same model, same year Sebring. Would it be possible that just because his car is on the same parking lot the alarm system of my car goes crazy and prevents me to start the engine? If so, is there an easy fix, like installing a switch which resets the alarm system? Anyway, maybe it is just a coincidence with the other car. What else could cause this behavior?

Thanks

Reinhardt

ANSWER: a big red dot is blinking on the dash when it does not start correct? and U have a gray key?   if both is correct U will need to have a dealer scan the skim module and see if U have a commutation error  only a dealer can program a new skim.

---------- FOLLOW-UP ----------

QUESTION: yes, that's both correct. I also read out the code on the odometer: P1685, which basically states that the key I not the right one. However, if I should believe the code, why is it then working afterwards at all?!? I will take your advice and bring the car to a dealer. Would there be any easy tests to perform myself, such that the mechanic saves some time while looking for the problem?

Thanks again,

Reinhardt

ps: I thought about getting an odb2 scanner anyway for later on. Do they show anything more than the error codes which appear on the odometer? I suppose only the profesional ones have access to the skim module, right?

Answer
the obd scanner that U would get will only read federal emission codes  there are over 2000 different codes that a car holds in the computer  and this is only one computer  the skim is just another one to add to the many U have on the car.
only a dealer can get into the skim   if any one could  they what would be the point of having an alarm on the car if any one could get into the car and start it up with a fake key?