New 12V & Car not starting

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by margaret walljasper, Feb 18, 2025.

  1. margaret walljasper

    margaret walljasper New Member

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    2018 Prius C was completely dead and had friend put in a new 12V Battery. The car lights, etc will now come on, but it won't allow driving. It says "Lane Departure Alert Malfunction" and "Pre Collision System Malfunction." How can I reset this so I can drive?
     
    #1 margaret walljasper, Feb 18, 2025
  2. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    The real way is to hook up a Prius-aware diagnostic scanner, read the details of the fault codes and use the tool to clear them.

    But sometimes you can get lucky by just briefly disconnecting the 12v battery and trying a fresh boot-up.

    The TSS sensor pod on the windshield (the thing with the cameras in front of your mirror) may be feeling cranky after its long nap, so it is certainly worth a reboot first.

    Also verify that the new 12v battery is charged to full, you should see around 12.7V on a voltmeter with the car shut off or battery disconnected.
     
    #2 Leadfoot J. McCoalroller, Feb 18, 2025
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  3. margaret walljasper

    margaret walljasper New Member

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    How do you reboot the sensor on the windshield?
     
    #3 margaret walljasper, Feb 18, 2025
  4. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Sorry I wasn't clearer about it- I mean disconneting your new 12v battery once more, but only for about 30 seconds. Then reconnect it and try starting the car again.
     
    #4 Leadfoot J. McCoalroller, Feb 18, 2025
  5. MAX2

    MAX2 Active Member

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    Is there a "ready" sign on the board?
     
    #5 MAX2, Feb 19, 2025
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