'06 Mazda 6 immobilizer malfunction
 

Last night I noticed the immobilizer indicator light on my dashboard was illuminated while driving my 2006 Mazda 6. When I turned the car off, the light stayed illuminated but was also blinking rapidly. I tested all the buttons on my keyless entry and they all worked fine. I was also able to start the car back up just fine. After arriving to work this morning, I had parked and turned off the car and went inside, I suddenly heard a car horn sounding continuously. Already knowing it was mine, I went out to try to make it stop. I was able to get it to go off but it continued to start back up. It finally got to the point where it wouldn't stop even after putting the key in the ignition and starting the engine. I disconnected the battery just to make the noise stop. Has anyone ever had something similar happen or know what the cause of this could be? I'm guessing it's some kind of malfunction with the factory alarm system. The only other thing I could think of is that I did have a remote starter installed about 6 months or so ago, and maybe something with that is interfering with the security system.

If its a new issue I would guess that whoever installed the remote start spliced into the wrong wire. It may also b the body control module. The mazda 6 had an issue with water leaking onto the BCM cause all kinds of funny problems.

Problem solved!
 

I figured it out.. I had used the button on my remote start to start my car while the key programmed for my car was hanging in the ignition, although not pushed in all the way, apparently that was enough to "confuse" my car into thinking someone was attempting to steal it. I was able to reset the immobilizer light on my dash by turning my key to the on position and leaving it there for 20 minutes, allowing it to reprogram.