2005 Gen 2 - Red Triangle, P3000 Code, ICE won't start

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Metrolens, Aug 22, 2025 at 5:44 PM.

  1. Metrolens

    Metrolens Member

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    I just had a catalytic converter shield installed by my mechanic on my Gen 2, 190,000 miles, but when I started the car to take it home from the mechanic, there was the Red Triangle, VSC, and the yellow exclamation in a Circle. The gas gauge also flashed repeatedly, from no bars to full bars, despite the car having recently been filled up with gas. On the MFD it also read "Problem," and the "Red Prius" icon with an exclamation point appeared in the upper left corner

    The ICE wouldn't start at all. On the MFD I could see the Hybrid battery had only 2 bars left.

    This morning I had driven the car to my mechanic with no problem. I have been using this mechanic for many years, and all he did today was install the catalytic converter shield. A few days ago he had also installed a brand new catalytic converter (since mine was stolen last week), but my car was driving fine with the new catalytic converter installed, until this happened today today.

    We tried to disconnect and reconnect the 12v (the 12v is still healthy, voltage reading over 13v, bought in 2018). We tried using an additional power source hooked up to the 12v. We tried adding gas (even though the car was probably 7/8 full). Nothing worked to get the ICE to start.

    Another factor (probably unrelated) is that my Combination Meter has been going bad, so sometimes I need to do the headlights-open door trick to get the dashboard to light up. So I thought, maybe the mechanic left the car running without knowing it, because the dashboard might have been black, causing the hybrid battery to run down? But this hardly makes that much sense, because normally the ICE would simply kick in if the hybrid battery gets too low.

    The mechanic ran his scanner, and pulled a P3000 code. He said the hybrid battery needed replacement. This is obviously very bad news. I replaced the hybrid battery once before, in early 2018, with a reconditioned battery from a place called Electron .

    Can anyone help with this? Can a Red Triangle suddenly occur like this, without any warning, and would it prevent the ICE from even starting? Am I missing something? Please help as my car is still at the mechanic and I need to figure out ASAP what the next step is going to be here...
     
  2. Tombukt2

    Tombukt2 Senior Member

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    You need the detail code that goes with that p3000 it's a three-digit code like 384 a scanner like AP 200 will get that detail code.
     
  3. Tombukt2

    Tombukt2 Senior Member

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    That narrows down your diag time
     
  4. Metrolens

    Metrolens Member

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    The mechanic just gave me the P3000 code, I asked if he had any other codes and he said no.
     
  5. Metrolens

    Metrolens Member

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  6. Metrolens

    Metrolens Member

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    There is also a U0100 code that is on the printout the mechanic gave me. "Lost Communication with ECM / PCM A"
    As well as P30000 "Battery Control System."
     
  7. Brian1954

    Brian1954 Senior Member

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  8. Metrolens

    Metrolens Member

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    I pulled codes using Torque and my Bluetooth adapter, and it didn't give any additional codes.

    The mechnic and I took another look to ensure that the oxygen sensor wires were not somehow damaged by the cat shield and touching the metal, possibly causing a short. The wires seemed to be fine. He is fully convinced that the hybrid battery has failed. It's a reconditioned 2013 battery which I bought from Electron Automotive back in 2017. And which has performed perfectly, until today.

    But would a failed hybrid battery completely prevent the ICE from starting?
     
  9. dolj

    dolj Senior Member

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    P3000 is set by the hybrid vehicle (HV) ECU, which means, "I heard from the battery ECU that it has a problem."

    This means there are codes set in the battery ECU that you're not seeing.

    While having the (one of three) INF codes could help, getting the codes in the battery ECU would be more helpful.
     
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  10. Metrolens

    Metrolens Member

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    How can I see those codes? Would an app like Dr. Prius show them using a normal Bluetooth OBD2 reader?
     
  11. Brian1954

    Brian1954 Senior Member

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    See post #7. The Autel AP200 will show you all the codes and sub-codes.
     
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  12. dolj

    dolj Senior Member

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    With a capable scanner, there is usually a button (or link) with a snowflake icon that gives you access to the freeze frame data. The INF (or sometimes labelled Detail) code or codes are in the freeze frame.
    While Dr. Prius is good for battery diagnostics, it can retrieve some battery codes, but it is not comprehensive enough to be called a scan tool.

    It will give you P0A80 and P30xx block codes and some others, which is better than nothing.
     
    #12 dolj, Aug 22, 2025 at 11:04 PM
    Last edited: Aug 23, 2025 at 2:53 AM
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  13. Metrolens

    Metrolens Member

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    Thanks dolj and Brian1954.

    Looks like the Autel AP200 is around $60 on Amazon, does that sound right? Would I be able to use it in both of my Priuses (2005 & 2016) without any kind of subscription or paying more for something?
     
  14. Brian1954

    Brian1954 Senior Member

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    Yes, the Autel AP200 (white colored dongle) is $60 on Amazon.

    You download the correct Autel app to your phone or tablet. Then, you create an online Autel account. Then, you pick Toyota as your free subscription and download the Toyota files into the app. You can then use the Bluetooth dongle and app on any Toyota car free for life. Please note that you need internet access on your phone or tablet to log in to the app, and you will have access to the app for one week without needing to log in again. If you need to use the app again more than one week since the last log in, you need internet access again to log in again. This could become a problem if you get stranded in a remote location where you do not have access to the internet and you need to log in to the app.

    If you want to use the Autel AP200 scanner on a different brand of car (eg, Ford, Lexus, Honda, etc), you would need to pay for a yearly subscription for that brand or buy a second Autel AP200 strictly for the other car brand.

    The other option is to install a hacked version of Techstream software onto a laptop computer and buy an OBD2 interface cable that works with Techstream. The installation of the software and driver for the interface cable can be a big challenge on a Windows 64-bit computer.

    The Autel AP200 dongle is very small and can be easily stored in the car, so you have it when you need it. It becomes more difficult to store a laptop computer and interface cable in the car.

    I have Techstream on a laptop, which I use at home, and I have the Autel AP200 which I store in my Prius.
     
    #14 Brian1954, Aug 23, 2025 at 12:00 AM
    Last edited: Aug 23, 2025 at 12:06 AM
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  15. Metrolens

    Metrolens Member

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    I was able to see how the mechanic installed the MillerCat on my Prius, and it seems he didn't feed the o2 sensor wire through the notch correctly.

    Photo #1 shows a correct install from the MillerCat website. The wire is supposed to be fed through the rectangular notch as circled in blue.

    Photo #2 shows my installation, circled in red. The wire doesn't go through the notch.

    Photo #3 shows how my o2 sensor currently looks inside the cat shield. The blue and white wires are bent because it's a tight fit, but are not touching the side of the shield. There's no metal on metal that I could see.

    Could the wire, if pinched or damaged or not fed through the notch correctly, lead to the Red Triangle and P3000 and the ICE not starting like I'm seeing? Or could these issues all be caused by a BLOWN FUSE?
     

    Attached Files:

    #15 Metrolens, Aug 25, 2025 at 11:20 AM
    Last edited: Aug 25, 2025 at 12:28 PM
  16. Metrolens

    Metrolens Member

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    Update, and a good one.

    I was right - all these problems were being caused by... a blown fuse! See pic for the fuse that was the culprit.

    20250825_134509.jpg

    After replacing the fuse, I drove around town for about 17 miles, to let the system recalibrate itself.

    Here's the result of my drive. The hybrid battery is charging and decharging exactly as it always has. I'm thrilled with how this episode ended. Thanks to everyone who chimed in with help/advice!

    20250825_150332.jpg
     
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