Help with diagnostic

I tried resetting my computer today (my airbag light is permanently on my dashboard) by taking off the battery. When I put it back on I have power but my car idles for 10-15 seconds then turns off. I still have lights and power. Could it be the alternator? Or is it a bad battery possibly? Or is the computer trying to re program itself
I made sure battery is well put and is charged it’s only a year old so not bad battery as everything seems to work except the car randomly won’t stay on
Was able to get my code reader and says it’s P2111 which is the throttle valve open just odd. Since I had no issues before
Thank you

 

P2111 is the TPS. May need to change. I think its built into the throttle body. Check for damaged wires first.

While its running for the 10 - 15 seconds try to get the voltage at the battery. I doubt its the battery since it starts up.

 

Perhaps a rodent chewed on some of your wires?