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12-Volt Battery drained during service

Discussion in 'Prius c Technical Discussion' started by HamboSchemery, Aug 25, 2022.

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  1. HamboSchemery

    HamboSchemery New Member

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    Hi all,

    Just had an interesting situation with my 2014 Aqua/Prius C

    Took it for a service, where it had an oil change and cabin filter replacement. All went well and I went to drive it home.

    On the way up a hill I suddenly felt the car go into limp mode, and then got a couple of warning lights on the dash (engine and hybrid battery light). I carried on trying to find a safe place to pull over. About 20 seconds later I lost all power, the engine cut out and the whole dashboard lit up with warning lights. Tried restarting it but got nothing.

    Eventually got it towed to my local toyota dealer. They diagnosed the fault being caused by very low voltage in the 12-volt battery, most likely caused by being left on during the service.

    Anyone heard of this happening? The garage is refusing to accept responsibility so I'm left to pick up the bill.

    Thoughts?
     
  2. Mendel Leisk

    Mendel Leisk Senior Member

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    How old was the battery?
     
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  3. Doug McC

    Doug McC Active Member

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    It could conceivably happen, based on my experience at the dealership when I got my first service: when they pulled the car out front they left it on when the kid parked it. No big deal as I had got tired of sitting and had decided to take a walk with in a minute or so of it being parked.
     
  4. HamboSchemery

    HamboSchemery New Member

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    Unsure. Potentially several years.
     
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  5. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    A dead 12v battery prevents a Prius from going into Ready mode. It won't cause a Prius that is already in Ready mode (driving) to go into limp mode, though.

    There is more to this than meets the eye. I would suggest that you next check and clean the battery cooling fan underneath the left rear seat.
     
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  6. Doug McC

    Doug McC Active Member

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    Assuming my understanding of the hybrid system is correct, what Leadfoot is saying is absolutely correct since in that mode the traction battery is charging the 12 volt battery.
     
  7. bisco

    bisco cookie crumbler

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    you need to read the trouble codes