Sweetie's Prius is Dead

Shel_B

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The problem turned out to be that the key wasn't communicating properly or well with the Immobilizer System. Using the second key, which had rarely been used since the car was purchased, has solved the problem. The battery and fuses were fine. Thanks to all who tried to help.
 
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Your dome light on, then going off after a short time means it isn’t all fine. It would be good to keep it on a maintainer charger or drive more. It’s a bit of an annoyance, but I started doing it recently. I was surprised even a 96 model has parasitic drain. I got a new WM value battery and it was great,12.7 volts. The vehicle slowly drains over time though. Both cars I have do it. So I have been checking the volts with a multimeter, or easier leave it on a charger with maintenance features. Keeps the battery topped up. The Prius has to be driven quite a bit to keep the battery fully charged.
 
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The problem turned out to be that the key wasn't communicating properly or well with the Immobilizer System. Using the second key, which had rarely been used since the car was purchased, has solved the problem. The battery and fuses were fine. Thanks to all who tried to help.

We shall now call it Lazarus
 
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I'm puzzled that this was caused by a dead keyfob. That doesn't explain the engine stalling...and doesn't the Prius have a "key not detected" alert if you try to start it without the fob on you?
The MFDs on the second generation Prius are prone to fail - and they are the “master” mode for some of the car’s body networks(Toyota calls it AVC-LAN, Honda calls their implementation GA-NET, both are based on NEC/Renesas IEBus - CAN and another Toyota-specific bus called BEAN also goes through the MFD), lose the MFD, a Prius can be “brain dead”.
 
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... Batteries don't last long in the Prius, ask me how I know, and you'll typically see other issues as they start to get weak. ... My gen 4 is on its third 12v battery in 5 years. ...
They last reasonably long if not abused. The $65 generic U1 AGM in my Prius is over 6½ years old and still doing its job, with none of the symptoms you listed. I've heard of them going over 10 years in other Prii.

Several ill-informed posters in this thread (not you) tend to confuse the relatively small, cheap 12-volt "accessory" battery with the large, expensive "traction" battery.
 

Shel_B

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Sounds like you've got a gen 2 or 3 with the 12v battery in the rear. Batteries don't last long in the Prius, ask me how I know, and you'll typically see other issues as they start to get weak.

FWIW, the original battery in sweetie's Prius lasted more than 10 years, closer to 11. Her current battery is about 3 years old, and the shop checked its condition ... almost like new.
 
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