What are some reasons why the immobilizer light would stay on with the key in the ignition? Car worked fine yesterday and then today it's just cranking, it won't even let me connect a scan tool to pull codes

 

That's the immobilizer part of the NATS system telling you the key isn't registered.

Sometimes the BCM just has a heart attack and loses the key RFID programming, sometimes the RFID chip in the key dies since they do only last a certain number of years before they die and need to be replaced.

I think the average life of an active RFID tag like the ones used in our keys is about 15-20 years. I should probably get my first OEM key replaced but I have a replacement that's only about 3 years old so it's tag will outlast the OEM one.

The immobilizer kicked in after 5 failed start attempts, that's why it doesn't crank anymore, if you plug in an OBD2 scanner you should have a code somewhere between P1610 and P1615 popping up depending on what triggered first, probably P1610.

EDIT: plug in the scan tool BEFORE you insert the key, it should power up when you turn the key to ACC.

 

i think it cranks.. i know i can hear something spin when i try to turn it on but it sounds like its spinning really fast... almost as if the starter is spinning but not popping out so it engages the flywheel

 

For starters, EXACTLY what does the NATS indicator light do. Here's normal function, insert the key and turn to ACC and the light will flash slowly, same when you turn to ON, and when you turn to START the light will be off and the engine will crank.

Anytime the light is SOLID RED while cranking it's due to NATS not recognizing something (usually the key) which will prevent fuel and spark, so the engine will crank but will not actually run because no fuel/spark.

If that's the case I would focus on the NATS system.

If that's NOT the case and it sounds differently when trying to start then you might have a failing starter. I've never actually seen a condition where the gear motor would run without actually kicking out the gear, this is mostly due to the way it's mechanically built on the inside and the contact doesn't close until the solenoid kicks out the gear. However electrical things like to short out and do weird stuff.

It's pretty easy to get the starter out if yours is mounted on the right/passenger side, it's pretty tight but it comes out, just pay attention to EXACTLY the angle it comes out or you're going to struggle trying to put it back in. You have to take the rear of the starter (which is facing toward the front of the car) and lift it UP and to the front of the car, basically tucking it up under the header, then you can rotate it to clear it's mounting flange and pull it out near the catalytic converter.

It will make more sense when you're under the car looking at it.

 

ok so then its for sure something with NATS because the light stays red. damn so that means i need to get a key made or reprogrammed?

 

Yeah that's almost always what that means. You 2006 is a bit more of a pain as well since the communication with the BCM takes place over CAN protocol not k-line, just make sure when you call around to locksmiths you tell them this so they can verify beforehand if their handheld programmer will work.

The dealership will definitely be able to program it though, if you end up going this route have your keys cut by an independent locksmith because it's much cheaper usually than having the dealership cut the keys. Call around and get prices.

 

ok so its like super weird.... now the light is off and i have no problem connecting my scanner but its still doing the same thing where it just sounds like the starter is spinning and i only head the fuel pump after i try to crank it...the other day when i went outside my gas tank cover was open so idk if someone ****ing with my car or what but theres alot of homeless around here -.- the only other thing thats kinda weird is my IDPM E/R had some relays that looked like there was some corrosion but when i pulled the relays and tested them they all worked

 

First things first, watch the crank pulley while someone else cranks the engine to verify that the starter is or is not engaging the flywheel. Also clean up the battery terminals, it might just be a weak battery or corroded connections limiting amperage to the starter so it just "sounds different".

If you hear the starter spin but the crank pulley isn't spinning as well then you need to pull the starter because something failed on it.

Have you ever had the starter removed? If so it may have not been properly torqued and a bolt fell out and it's just not engaged on the flywheel anymore.