2004 Prius Lost Power while Driving... help?

Just had a rough experience in my Prius that I want to share, and see if anyone has any useful insights....

Last Friday, my 2004 Prius, with 100,700 miles on it (700 miles past my extended warranty!!!!), died while I was driving it. While I was driving on the freeway, the red triangle master warning light came on, along with the MFD warning light, check engine light, and the (( ! )) light to the right of it.

After a few minutes, the red parking brake light came on, along with a constant beep/alarm sound. When this happened, I was in the process of exiting the freeway and trying to find a safe place to pull over.

Unfortunately, a few moments later, while I was stopped at a traffic light, this message came up...

"The transmission P lock mechanism is abnormal. Park your car at a flat place, and apply the parking brake completely."

And the car wouldn't budge.

I tried restarting the car a few times, and got it working again -- interestingly the warning messages were all gone -- and was able to move a little further down the road before the whole thing happened again.

I towed the car to the Toyota dealership, and after spending a few days on it, they came back and said that this was all caused because I ran out of gas.

I don't buy it. Yes, the low fuel light had just come on, but I knew I was good for at least another 40 miles (I had put in 10 gallons, had driven 380 miles to that point, and have been averaging 450 miles between fillups). Also, after the first time the car died, I was able to drive it an additional 1/4 mile using the ICE engine... so there definitely was some gas left.

After searching these forums, I suspect that it could be because my 12V battery is still the original one, and is due for a replacement. But could a bad 12V battery cause all these problems while the car is being driven??? It seems I should've seen some symptoms at startup first...

I've driven the car another 25 miles since I got it back from the dealership, but I'm worried that the dealership's diagnosis is incorrect and that the problem is going to come back...

 

Thanks for the reply, Bill.

The thing is, I had done a search before I posted, looking for the anything dealing with the error message "transmission lock mechanism is abnormal"... and every one of these posts talk about the 12V battery or something worse... I didn't see one that says it's a symptom of no gas.

 

I understand, but again, what does that have to do with the "transmission lock mechanism is abnormal" message that constantly came up? Unless I'm doing the search wrong, this has nothing to do with running out of gas.

 

Thanks for all the feedback everyone... I now know the signs of what to watch out for, and will refuel well in advance...

I'll think I'll replace the 12V battery as a precautionary measure too.

A little backstory why I didn't totally trust the dealer... after a Prius tech road testing the car, they told me that the center display was bad, because..

1) They put in 3.5 gallons of gas in, and the gauge is now showing half full (we all know the gauge can be inaccurate, so this I disregarded)

2) They told me that the speedometer was busted because it was showing a speed 20 miles faster than the tech was driving.

The dealer wanted $895 to replace the part + labor.

I was exceedingly wary about this because I thought I would've noticed a 20 mph difference in speed... so I declined the part, and asked to get my car back to see the problem first hand.

By now, I bet most of you could guess what was wrong... the speedometer was set to km/h!