[badhat]

It was running for a bit while I was checking the ATF and front diff levels -- I added about 100ml to the diff since it was closer to the L than F... then turned on the car.

Came back outside 20min later and tried to start -- it does start initially but then immediately dies. Lights stay on so obviously not a battery issue.

 

[jgrote]

I bet you knocked something loose on one of the wiring harnesses by the front diff fill. There are several large plugs there that are crucial for the car.

 

[badhat]

Welp, I waited until this morning to take a look and I couldn't really find anything obviously knocked loose so I tried starting the car again -- this time it worked flawlessly.

Any other ideas as to what may have caused it to quit out so easily? As I said, all I did was add a little front diff fluid (~200ml) to top it off.

 

[slowhatch]

That sounds like an immobilser fault. I don't know if your model year has an immobilser but if it does that could be the cause. That is exactly what the cars I work on do when there is a fault. If it does have an immobilser, it may not have been reading the chip in the key. Just a thought. Hope you don't have anymore issues. That would bother me if I didn't figure it out. I don't like having doubts about whether my vehicle is going to start or not. Good luck, Dave.