P3000 & C1310 codes -- troubleshoot sequence?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by brka-brkb, Dec 13, 2025 at 8:57 PM.

  1. brka-brkb

    brka-brkb New Member

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    Good evening!

    My 2005 Prius with 94K miles is showing P3000 & C1310 codes with the red triangle after sustaining a light water damage (i.e. floodwater got into the car but did not go above the floor level) earlier this year.

    The trustworthy local auto mechanic says the range of possible issues--likely tied to hybrid battery--is too broad to be worth the likely cost of the repair ($4,000-$5,000) given the age of the car, but the car drives fine and as you can see in the attached photos, it's otherwise in a pristine condition so I'd like to at least do my due diligence and attempt to troubleshoot what could be wrong with the car.

    1. What would be the logical initial troubleshooting steps to take?

    2. Would getting a new (or refurbished) hybrid battery possibly be a better option? If so, from where?

    Thank you very much and happy holidays!

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  2. ChapmanF

    ChapmanF Senior Member

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    P3000, if I remember right, is kind of a catch-all code in the HV control ECU for a bunch of different conditions, and will have an associated 3-digit INF code that you really need in order to know what it's going on about.

    Here is a thread about scan tool options that will be able to read the INF code:

    Gen2 OBD2 app review | PriusChat

    The C1310 you don't need to worry about. That's the brake/skid ECU saying it knows there's a code from the HV control ECU (i.e. the P3000 you already know about).

    The P3000 in the HV control ECU might (or, again, might not) be set because of some other code set in the battery ECU, and sometimes people get codes using scan tools that can't communicate with all the ECUs in the car, so might be reporting the code in the HV control ECU but not reporting a code in the battery ECU even though one might be present.

    A scan tool recommended in the thread linked above (for showing INF codes) should also be able to talk to all the car's ECUs and so not miss any codes.

    I would not try too hard to guess at what the problem might be, before getting the rest of the information the car wants you to have about it.
     
  3. PriusCamper

    PriusCamper Senior Member

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    You've taken wonderful care of your car and you deserve to keep it on the road at a reasonable price!

    Your mechanic is predicting the upper end of the repair cost because they likely don't spend enough time working on hyrbid cars to know how easy the fix can sometimes be.

    Best case scenario, your P3000 means corrosion from the hybrid battery terminals made its way to battery ECU and is sending bad signals because first pins in plug are starting to create micro-shorts/signal noise. I was just working on a battery pack today with this problem and it hasn't even yet thrown the error code, but it will soon had I not cleaned it out. (See pic below)

    Do you have a friend or family member, or do you have basic skills working on cars? Cause all us folks at Priuschat can walk ya'll through any repair and you'll save a fortune.

    And if it becomes certain problem is not as easy to fix as described above and will cost more we can walk you through the other options that could go as high as 1/2 the price the mechanic estimated.

    In meantime, buy one of these for your glovebox: http://www.ebay.com/itm/265484403768 It only costs $20 and can one day be the difference between waiting for a tow truck and just clearing error codes and driving home. As in this device plugs into socket under dash near steering wheel and allows you to connect phone to car diagnostics via phone apps like Dr. Prius app.

    For example, if you used this device to post a screenshot from Dr. Prius app tonight we'd have enough info to confirm that you have the least expensive hybrid battery warning light repair.

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