2010 Prius NO CODE--Won't READY!

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Jonesy23, Jun 28, 2026 at 10:17 AM.

  1. Jonesy23

    Jonesy23 New Member

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    my 2010 Prius started to lag on the highway. I quickly pulled over and tried to start it again and it would not go into ready. I bought a new 12V from Toyota it still won't go into READY. Odd things is there are NO CODES and NO TRIANGLE just the "Christmas Lights" on the dashboard. It is saying Shift to P to start and I checked the brake lights and they are fine. I checked under the shifter by pulling up the cover and all wires are connected. It's getting worse because the hybrid battery is dying as it's not being DRIVEN. It did say shift to P low traction battery but I don't know if that is because the hybrid battery is dying slowly which I may have to replace BUT I need to get to the origianal problem b/c if I gat a new hybrid battery and it still won't start this will not be good. Also, changed the inverter water pump and added gas to the car. I hear clicking in the back of the car near the 12 volt but it won't turn over. I tricked charged and tested 12 volt was nice and strong again after all this trouble shooting and still won't go into ready. I have the Dr. Prius app and it reads codes on my other prius so it's not me...this car is not giving me any codes not even a check hybrid system code only pops up once I disconnect the orange plug but when I put it back it no check hybrid system code.....I am so lost with this one. Please help. Thank you.
     
    #1 Jonesy23, Jun 28, 2026 at 10:17 AM
  2. JC91006

    JC91006 Senior Member

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    If your car died while driving, you either ran out of gas or your inverter has likely failed. There should be codes if you have a Prius capable code reader
     
    #2 JC91006, Jun 28, 2026 at 10:04 PM
  3. rjparker

    rjparker Tu Humilde Sirviente

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    Dr Prius won't read all the codes.

    There should be codes if it suddenly stopped but we really don't know that because you said it was lagging.

    What "gear" does the display show?

    Do you do the coast in Neutral trick when you are driving? If it was in Neutral the hv battery can't charge.

    Have you been clearing codes by disconnecting the 12v battery?

    Are you sure you swung the hv disconnect in then pushed it sideways?

    An inverter fail can be sudden. An over temperature can cause a lower power limp mode. These will code.
     
    #3 rjparker, Jun 28, 2026 at 10:29 PM
    Last edited: Jun 28, 2026 at 10:34 PM
    Brian1954 likes this.
  4. Brian1954

    Brian1954 Senior Member

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    Use the Dr Prius app and look at the voltage of the battery at the top left side of the data screen. Please post the voltage of the battery, and we will go from there.

    I would ask you to post a screenshot of the data, but you can not add file attachments or links into your posts until you have reached 5 posts. It is standard for new members to be moderated. That is why your posts are delayed.
     
    #4 Brian1954, Jun 28, 2026 at 10:37 PM
    Last edited: Jun 29, 2026 at 8:27 AM
  5. Jonesy23

    Jonesy23 New Member

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    Hi and thank you for trying to help me. I added gas after it got towed home it still would not start. I read using Dr. Prius and there are no codes on this car, my other Prius has codes.
     
    #5 Jonesy23, Jun 29, 2026 at 8:15 AM
  6. Jonesy23

    Jonesy23 New Member

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    As you can see the battery is getting worse from sitting. I
    1. changed the inverter water pump.
    2. Bought a nee 12 volt
    3. Added gas to the tank
    4. No triangle of death
    5. No codes.
    6. It won't go into ready
    7. Do you think cell 10 is the problem?
    8. Wondering if chaning the water pump clearned the code. My son said whatever poppled on the display in the book said it was the water pump so I changed it without reading codes at first.
    9. Do you think the 12 volt is not sending enough energy even when it was bradn new...this is just too much. I want my Prius back on the road.
    10. 10. Do you think it's the EGR?
     

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    #6 Jonesy23, Jun 29, 2026 at 8:23 AM
    Last edited: Jun 29, 2026 at 8:35 AM
  7. Brian1954

    Brian1954 Senior Member

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    III
    Start by charging the 12v battery. The two screenshots show 10.8 and 11.3 volts. After getting the 12v battery charged up, use the DrPrius app again. If the hybrid battery voltage is still low, proceed to the next paragraph.

    I have never seen a Gen 3 with such a low hybrid battery voltage and 0.00 % state of charge. The engine must have stopped running, and you continued to drive the car using the hybrid battery. The only way to get the car running again is to use a grid charger to charge up the hybrid battery. A Toyota dealership can charge the battery, but it will not be cheap. Normally, the hybrid battery has a voltage of 215 to 230 volts.
     
    #7 Brian1954, Jun 29, 2026 at 6:28 PM
    Last edited: Jun 29, 2026 at 6:38 PM
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