2007 Prius: Red Triangle + ABS + Engine Check lights :(

Discussion in 'Gen 2 Prius Main Forum' started by Lindsay Mathieson, Nov 22, 2025 at 6:45 AM.

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  1. Brian1954

    Brian1954 Senior Member

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    I would leave it on for another 8 hours since it is only a 2 amp charger. After you remove the charger, let the car sit for a few hours, then check the voltage the same way you did before. You can then clear the trouble codes and let us know if any warning lights come back on.

    If you do not drive the car and it sits for 3 or more days at a time, week after week, then it is a good idea to use the charger every 2 or 3 weeks. The charger you bought is a smart charger, so it will not overcharge the battery. You could leave the charger connected to the battery for months without a problem.
     
    #21 Brian1954, Nov 23, 2025 at 9:41 AM
  2. Lindsay Mathieson

    Lindsay Mathieson Junior Member

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    Ok, rechecked the battery first, showed 11.8v :(

    Cleared the codes, restarted and rechecked - stayed clear except for the AirCon passengar sensor, which is always on when parked in the carport :)

    Took her for a short test drive, ran well, no warnings came up. Did an emergency stop and brakes seemed fine.

    Rechecked the battery and it was 12.1v

    Checked the Inverter Coolant Pump, lots of turbulence, definitely running.

    Cautiously optimistic, will take her for a longer highway test sometime soon.

    Thanks for all the help and advice!
     
    #22 Lindsay Mathieson, Nov 23, 2025 at 6:48 PM
  3. Brian1954

    Brian1954 Senior Member

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    III
    11.8v is low after you charged it. Did you charge it for about 12 hours? Do you know how old the battery is? If you do not know, maybe you can post a picture of the battery. Most batteries have some type of date code on them.

    You may be right that the battery needs to be replaced. The original battery in the Gen 2 Prius for North America was an AGM battery. There were two different sizes depending on whether the car had SKS key fob or not.
     
    #23 Brian1954, Nov 23, 2025 at 7:32 PM
    Last edited: Nov 23, 2025 at 7:50 PM
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  4. Lindsay Mathieson

    Lindsay Mathieson Junior Member

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    Yup, 12 hours, 3:30pm - 3:30am.

    I'll see if I can dig up the battery info, it is AGM.
     
    #24 Lindsay Mathieson, Nov 23, 2025 at 8:52 PM
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