SKIM/Immobilizer disabling and removal,
this subject has been discussed but I could not find a sticky for this subject! I have posted this on www.neons.org
too infact I just copied all I posted there and put it here
From what I understand from posts on this forum and others.
If a new uncoded (or specifically flashed Engine Control Unit/Module) is fitted it will see that there is a security code from the immobilizer/security module or from the wiring to the receiver from around the ignition barrel and say 'Oh we have security protocols what's the code?'
If you change the keys, instrument cluster, ECU/PCM or immobilizer module, or skim ariel you will have to reprogram everything. The gauge cluster, pcm, and skim module (key box&key) must all agree and have all the same vin programmed into them. if you had all three, the skim would never even know it's been moved! If you have the key, module and pcm, they can and will program the gauge.
But if you have access to a drbIII you can reprogram the VIN with the computer in the car if you wanted to!
The Key fob has nothing to do with the skim. the chip is in the key. Once the 'sentry' feature is activated on a ECU/PCM, it can not be 'de-activated', but it can be changed or made blank ready for a new car.
However if a car has had the immobilizer and the sentry system removed including the SKIM ariel around the barrel, and an uncoded ECU/PCM is fitted it will work without the need of a skim and the immobilizer or the need to be programmed regardless of staged or stock cluster
This is what a SKIM ariel module basically looks like (Borrowed from a Jeep forum):
The sentry key only needs to be seen when the car is initially started, after that, it doesn't care where it is. You could actually use a cheap key and start the car with the sentry key next to it. once its started you can put the sentry key away and car will run fine. So alternatively if you wanted to fit a remote start kit you could remove the chip from the key affix it near the ariel and put the ariel under the dashboard if you didn't want to flash the ECU/PCM and remove the immobilizer.
The Quote below is on the neons.org forum but took some finding to quote "NOS2006"
Not sure exactly how much significance this has on us Neon owners, but I think it's a pretty interesting find...
Cliff notes: it basically tells why you have to program a PCM with a SKIM and gives a phone number where you can supposedly call and rent a DRBIII.
EDIT: Here's another page I just found. Not Chrysler-sourced, but page 2 is pretty informative: