Could be the battery was just that tapped out and even the alternator couldn't keep things going. Were you moving/accelerating when this happened? I'm assuming so because you say you were at about 1200rpms. Did you check the terminal connectors to make sure they were tight on the old battery? A loose one could have been causing intermittent contact.

You may still want to have the alternator checked out because we don't know how long it's been overworking keeping the old battery kicking, and it may be worn out from that. Everything looks fine right now though from what you're showing us.

The main thing that comes to mind for me when I think about this is broken or intermittent contact. The other thing would be that the battery was deader than dead. It is odd that it shut down above idle speed.

 

Thank you SaGa. Yes, I was accelerating at the time and only my low beams were on. I spend some time just now looking at the old battery and it seems that the positive post is a little loose Internally on the battery ( maybe its not making secure contact with the cells in the battery).
I'm just a bit curious as to why it shut off. I will have the alternator tested as the winter is coming and it would add more stress to the electrical system.
Also the ECM recall was performed a couple of months ago.

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Well particularly with the positive terminal, if you lose connection on that side of things the car will shut down. If the terminal is loose that could be the culprit along with that battery being pretty far past its prime.

 

yeah sounds like the battery couldn't help regulate load since it was so far gone. could have been a corroded/loose connection as well that was fixed when the battery was replaced.

i'd check the voltage on your battery over the next few weeks to make sure the alternator is maintaining the appropriate charge. 13.9V is fine with the car running, but after the car is off and has sat awhile, the battery should read about 12.6V. checking it in the morning before you go to work is the best time. you don't want to do it too soon after the car has been running since you will have surface charge that will throw the numbers off.

 

These cars have what is called "smart" alternators which shut down down when a severely discharged battery is detected.

It sounds like your battery was just completely toast.

I would be surprised if you didn't see symptoms before like a weak or slow crank.

 

really? my wife has a 2005 solara and i've tested the alternator only scenario by disconnecting both battery terminals once the car was running. i'm assuming the car would have shut down if such a "smart" alternator was in place, but it did not, it kept humming along like normal.

 

this just happened to me two weeks ago. tried to jump start the car with my other it did not start. i thought something else was wrong (starter) called toyota for entended warranty in case something else is wrong and had the insurance tow it to the dealership in case its sonething not covered. came out to the battery just being totally gone. was happy nothing else was wrong but was hoping something would be replaced under warranty.

 

So I just checked the voltage at my battery terminals.
12.65 at rest
14.00 at idle
13.90 at idle with high-beams and heater on max.
I think the alternator is running good so I see no point in taking it out to have it tested.
Thank you all for your assistance and information.

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I think you're fine given those results. Did the old battery just go kaput out of nowhere, or had it been showing signs of wear and age when you would start the car? 8 years is a long time on any battery. I think my original one only lasted about 5 or 6 and it was definitely telling me so by the end of its life when the cold weather would roll around. Similar to you, though, it was fine when I drove it home and parked it. Then later the same evening when I went to go start it just to move it to another spot in the driveway, the car was completely dead.

 

Last winter you could tell that it was approaching the end of its life. Then warm weather rolled around and it was a lot better. I was going to replace it in a month or so anyway.

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