'06 Scion Tc starts then shuts off in two seconds

Question

My fiancé drove the car with no problems this morning. After work she realized she left an interior light on which killed the battery. She got a jump from a car and charged the battery up a bit. Now the Scion will not stay on after a couple seconds? I can't really diagnose the battery voltage and alternator if the car doesn't stay on?

I don't have my code scanner with me. The car starts perfectly then it just turns right off with no sputter. The car has never done this before. It literally stays on for 2 seconds and turns right off.

From my knowledge it does seem to be a security feature. The car is mechanically in great condition. It also has a remote starter that works just fine. I checked the spare key to make sure it wasn't the chip inside the original key but no luck.

There isn't anything on the dash indicating the problem except for the tire pressure sensor that has been on and I can't tell if the CEL is on or if the car doesn't stay on long enough for the light to turn off as to when you first start the car.

Answer 1

This sounds like the immobilizer is kicking in (although the VW ones that I've dealt with allow the engine to run for about 30 seconds before shutting it down).

On the dash there are lights that should give you feedback on the immobilizer status. They usually look like a key. It should come on briefly when you start the car to indicate that it is working, but then it should stay off. Does the light come on after the engine shuts down? That would indicate an immobilizer fault, probably due to the low battery.

Without further information the best advice I have to offer is:

1. Check for the immobilizer light after the engine shuts down.
2. Fully charge the battery.
3. Check your owner manual for details about the immobilizer system, they may document a procedure for dealing with recovery after a dead battery.
4. Talk to a dealer or Scion shop. The immobilizer is supposed to be hard to bypass.
5. If you don't have any immobilizer related indicators, add that to the question and read the DTC codes (and fully charge the battery).

Answer 2

Car shouldn't start with an OEM immobilizer issue. Just "crank".

Remove fuses/disable remote start first.

Keep a battery charger on battery while attempting to start.

If the car was boosted backwards it wouldn't crank so you can rule that out as well.