So, this is really weird...
I was out at lunch drove around, came back and sat in the parking deck for a minute having a smoke, no problems at all.
I get ready to leave work for the day, go get in the car, I'm getting ready to go and I get a call, sit there for a minute with the key in position 2 while I'm on the phone and all of a sudden the info screen pops up a Transmission fault warning, weird, just sitting here not cranked...
Get off the phone and try and crank it up, and low and behold it won't run...
It cranks fine, gets started, starts throttling down and then dies. Over and over again... I can get a little rev out of the engine if I hit the gas right after it cranks, but it still dies after about 2 seconds.
Nothing I can do will get it to crank and stay running...
Any ideas???
I don't really want to be stranded at work tonight.

 

Sounds like a MAF or a Throttle Body or a thermostat to me. Weird about the tranny fault though...that sounds battery related.

 

Crank position sensor? I have never had one fail but have been told the vehicle will crank over and start, then immediately die. Good luck.

 

Let it sit for a while. I had a similar situation where I turned it off, then turned the key back to position 2 to shut off the radio, came back out 5 minutes later and it didn't even crank. Tried a few more times and got a transmission fault message, stuff was acting really weird. Got out, let it sit for a bit, got back in and it started right up with no problems. Looked at the codes and the only one was for the immobilizer. These things have serious glitches sometimes.

If it still doesn't start, then you likely have more than just a glitch.

 

Yeah the shut-off seconds after running is a classic immobilizer indication.

Do you have a second key fob? They have independent IDs in the immobilizer - it's possible one's battery has finally failed (they're sealed/rechargeable). In that case the other key should work fine.

 

JK forget that - apparently the LR's won't let the vehicle start at all. Some older vehicles (and VW/Audi etc) will let the engine start but shut it off after 1 second or so).

Plus if it forgot the fob, odds are keyless entry wouldn't work. It would be more likely that the scanner ring for the key ID had failed - but again apparently none would allow start of the engine.


Have you had a fairly rough idle lately? Could this be as simple as a REALLY dirty throttle butterfly?

Does it ALWAYS shut off at the exact same time interval, or does it sputter or run longer sometimes than others? That would tend to indicate electrical vs. mechanical like dirty butterfly.

 

My (bad) advice:

clean throttle body butterfly plate
clean MAF (rubbing alcohol in a pinch)
check voltage on battery, may be too low
brake light switch has been known to cause crazy faults
cold weather caused some low voltage faults for me on first start

Not sure its a thermostat issue, they typically throw a CEL when they fail, and you can still run the motor fine in temperate weather, thank god they usually fail OPEN

It sounds like how my truck acted when I killed an alternator. Idled horribly, and the transmission faulted then would only shift into 3 or 4 gears. EDIT: read your description more carefully, not the same as mine... sorry

If you don't have a tool to clear the faults, disconnecting the battery and holding the cables together for a min or two worked fine for me when I needed to fix an issue.

Hope it improves.

 

To add to that, the immobilizer chip works regardless of a dead battery.

 

SO, got an update... Went down to the office this morning to see what the deal was...
Been sitting with all the infotainment crap disconnected completely for a couple or days.
Get in, turn the key... Same thing, cranks and dies within 2 seconds. Turn it over again, and it fires up, although with the transmission in limp home mode. Since there are some pretty major hills between my office and the house I decided not to try and drive it home, but to at least put it in the bottom of the parking deck so I can actually get it on a tow truck.
So, get down on the ground floor and pull in a parking space and decide to try and turn it off and back on to see if the transmission fault would clear. Back to not starting.

I did notice however that it's not a fixed time before it dies, there is a little bit of variance. And I can get it to rev up every once in a while if I punch it right after it starts, but it lugs down and dies very quickly none the less... Throttle body moves nice and freely with the key off, trying to start it, it doesn't move as much as I would think it should to try and run the engine from start, maybe that's just my bad perception though.

I did get the transmission fault to go away by plugging my mongoose in and then unplugging it... Didn't scan or anything, wasn't even hooked up to the pc, just plugged it in and unplugged it... Transmission fault gone, and now "Tire Pressure Monitoring system Fault" instead... Still wouldn't run though. I didn't have my regular code scanner with me so I wasn't able to pull the codes...

Any thoughts?

 

Sounds like you have some communication issues. Was there any heavy rain before the incident or a washing of the engine bay?

Try removing the battery and behind it you have the transfer case ECU and engine PCM. Remove those and check contacts for corrosion. Clean all contacts with electrical contact cleaner.

Its hard to say for sure without codes, but the above is free, just takes some time.