A used ECM can work. However, often times it needs to be flashed (which is like resetting it). As far as the security light, something isn't recognizing the key you are using and the vehicle thinks it is being stolen. Frustrating to say the least.
As far as scanners, the reason I recommend a dealer is because they will have a scanner that can read that system of the vehicle. Most inexpensive scanners work fine to read engine trouble codes, but they are limited and usually can't read other codes that the computer can store. I believe that may be what is happening.
Tuesday, March 10th, 2015 AT 5:11 AM