This is on my 2008 3.0 Outback.

When the engine is cold, the car will start right up, idle for about 1-2 seconds and then shut down like the engine was turned off. If I immediately turn to start again, it will crank but not start. When this started happening 2 months ago, if I turned the key off and then back to start it will start up normally and continue running. Over the last couple weeks is has gotten worse, sometimes taking 10-12 start/stall cycles before it will stay running. I can sometimes prevent it from stalling by using the throttle to keep the revs up for the first few seconds. 

Once it stays running through startup, it will run great with no idle or stalling issues. 

When the engine is warm or hot, it will start up normally.

I do get occasional 0420 code, but I have been getting that for a while, the starting issue is only for the last month or two.

I have had the car for about 14 months, I did the head gaskets last September. Other than that it has been running strong.

Over the past few weeks, I have tried;

1. Turning the key multiple times to on before starting to cycle the fuel pump. 
2. Cleaning the MAF
3. New battery
4. Logging multiple sensors with ROMRaider during multiple start/stall cycles.
5. Different keys (due to immobilizer codes)

ROMRaider gives codes P1572 and P1578 but they don't trigger a CEL. 

Any thoughts on where to look? I do have Free SSM and the ROMRaider on my laptop if any of that data would help?

Hey D, hope you had fun at the dragon. 

Is this an all stock, US vehicle?  
No custom alarm or remote or wireless starting add ons? 

Maybe battery condition, clean battery posts, and check terminals for corrosion.  And grounds if there are any obvious ones to check. 

Seems like an immobilizer/key issue.  But I have no idea how to diagnose that.  You said multiple keys had the same issue....

Does the FSM offer any insight into those two codes?

We didn't make it to the Dragon this year. 

Bone stock, OEM Keys programmed at the dealer. 

I thought maybe the battery was the issue, so I put a new one in, the terminals are clean. 

I checked the grounding straps going to both heads. 

I want to check grounds around the ECU.

The FSM doesn't give a lot of info on those codes. 

Can anyone tell me what happens if a key without the immobilizer chip is used to start? Does it crank, but not start or does it do nothing?

Here is a video of the initial start/stall this morning... 

 

2 minutes ago, Hocrest said:

 

Can anyone tell me what happens if a key without the immobilizer chip is used to start? Does it crank, but not start or does it do nothing?

Great thinking - if you find out I'd love to hear the verdict.

Does the ignition sound or feel any different? Not sure how this impacts immobilizer but car shutting off is mentioned in this subaru recall:

https://static.nhtsa.gov/odi/rcl/2019/RCRIT-19V297-1387.pdf

 

cars101.com says: 

Quote

If an incorrect key is used, the car will run for a few seconds and then shut off. If that happens, remove the key, wait a few seconds, try again.

http://www.cars101.com/subaru/keyless.html

5 hours ago, idosubaru said:

cars101.com says: 

http://www.cars101.com/subaru/keyless.html

This may be it???? I just pulled the lower dash apart and disconnected the wires going to the antenna and reconnected everything. It just started and stayed running 4 times in a row! Just a few hours earlier when leaving work, it took about 20 start/stall/remove key cycles before it stayed running.

We'll see ho it acts over the next few days?

9 hours ago, Hocrest said:

This may be it???? I just pulled the lower dash apart and disconnected the wires going to the antenna and reconnected everything. It just started and stayed running 4 times in a row! Just a few hours earlier when leaving work, it took about 20 start/stall/remove key cycles before it stayed running.

We'll see ho it acts over the next few days?

That would be a sweet fix.  Good thinking on the connector - is it low enough that it might get some snow and debris from wintry footwear or boots?  I don't think any EJ wires are that close but wondering if there's anything causative going on.

It is still acting up, since taking it all apart, it is now down to 2-3 start/stalls which is much better than the 10-12 it has been in the days prior. 

 

I had the original key and a new key programmed at the dealer last year. It gives the same issue with both keys. 

 

I am going to swap out the antenna first, since that is cheap and doesn't require programming. If that doesn't work, I'm not sure other than taking it to the dealer??

If I swap the ECU/BIU and Gauge cluster, I think I also need the original key that is coded to that set or even the dealer can't reprogram??

Oh shoot I see you haven’t fixed this.

Do you think it could be that ignition switch recall?

I saw references to others chasing this and replacing a variety of parts with no resolution. Never saw anyone mention antenna though. 

Guess I’d see if the FSM has any immobilizer trouble shooting chart or if there’s a way to test the gauge/etc for immobilizer functionality.  

coupla wild ideas; when you were monitoring the sensors, how did the engine temp sensor look? ?

 

also, is this the first year of DBW? could this be electronic throttle problem?

29 minutes ago, 1 Lucky Texan said:

also, is this the first year of DBW? could this be electronic throttle problem?

no not the first year... other half's 06 is dbw on the throttle

The logs for the engine temp sensor looked normal.

I am fairly certain that it is the Immobilizer acting up. What I didn't notice at first is that every time it stalls out, the "security" lite comes on.