Red triangle, no codes, need help with next steps

Discussion in 'Gen 2 Prius Main Forum' started by Jbird610, Feb 1, 2025.

  1. rjparker

    rjparker Tu Humilde Sirviente

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    You may be able to use the Dr Prius phone app with your fixd bluetooth obd2 interface.

    Special functions , Read battery errors
    IMG_7355.jpeg
     
  2. Jbird610

    Jbird610 Junior Member

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    This is what I found. The low bars in the middle seem Screenshot_20250203-213353.png concerning
     
  3. dolj

    dolj Senior Member

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    The way the Dr. Prius app graphs the block voltages exaggerates the difference. You only have a 0.22 V (which is not the best) difference between the highest and lowest block. Having said that the data is pretty meaningless as you have no charge or discharge current. Static voltage does not tell you much.
     
  4. highmilesgarage

    highmilesgarage Active Member

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    where is that report coming from? FIXD? if you're using Autel then go to the Hybrid Battery module and diagnose from there. OBD2 (ECM) will give you nothing..
     
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  5. MAX2

    MAX2 Active Member

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    It is likely that the freeze frame was taken after resetting the errors and does not contain significant information.
    Check the battery using the Hybrid Assistant application under load.
    The graph of the Reporter menu of the Hybrid Assistant program will show the difference between different pairs of high-voltage battery modules.
    As a rule, during discharge, the modules of a faulty battery discharge with different values.
    When one of the pairs of modules suddenly loses its voltage, this indicates that there are one or two faulty modules in the pair.
    When the difference between pairs of modules located next to each other exceeds 0.3V, the battery ECU records an error and the red triangle of hybrid system problems lights up.
     
  6. ChapmanF

    ChapmanF Senior Member

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    Dr Prius can show you (some) trouble codes from the car. Anyway, if the triangle is showing, that's what you need to ask Dr Prius for—the trouble codes, not its page of battery health info. The codes you have might not even be about the battery.
     
  7. MAX2

    MAX2 Active Member

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    Yes, there can be many problems in a hybrid system and they are not always related to the high-voltage battery.
    Dr. Prius can give a code, but not indicate the error subcode. Not very informative.
     
  8. Brian1954

    Brian1954 Senior Member

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    The OP said in post #18 that he has P0AA6 trouble code.
    The OP needs to get the sub code for P0AA6 to narrow down where the problem is at.
     
  9. ChapmanF

    ChapmanF Senior Member

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    Oops, missed that, sorry.

    The P0AA6 subcode (611, 612, 613, or 614) will tell you which of these areas of the car to be looking in:

    [​IMG]

    If getting the use of a scan tool that can show the subcodes is too much trouble, you can search PriusChat for posts about how gen 1 owners dealt with P3009 (the code Toyota used in gen 1 for the same condition, before SAE standardized P0AA6). There wasn't a subcode with that one, but by clearing the code and then observing when it comes back in a careful startup sequence of the car, you could get the same basic idea which area of the car has the problem. The P0AA6 subcodes basically come from the car doing the same thing for you, on the next start after P0AA6 first appears.

    Gen 1 didn't have electric A/C, so you have one more step: if you go through all the gen 1 steps with the A/C off, and the code never comes back, then you turn A/C on and it does, you can take your subcode to be 611.
     
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  10. Jbird610

    Jbird610 Junior Member

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    After investigation of problems, I discovered that this generation notoriously develops a leak in the hatch. We did have water under the 12v.
    I found a crack in the hatch and sealed it hoping that would cause the fault error to go away but it didn't.
    I took the car to 2 different friends with more advanced scanner and neither scanner showed the subcodes. The 2nd friend said he would look through the data more but I haven't heard from him.
    One friend found more codes that my reader wouldn't pick up, including B1421. One of the suggested remedies was correct coolant bleeding. This made me wonder if I hadn't bled the coolant line currently. So I bled it today and got the air out.
    I'm still getting the red triangle, but the last time I read the codes, I still get the P0AA6 in the Cruise control.
    These are the codes my friend found:
    C1310 malfunction in HV system
    C2122
    C2123
    C2124
    B1421 solar sensor circuit (passenger side)
    P0000 transmission control
    P0AA6 hybrid battery voltage system isolation fault
    B1248 AVC-LAN communication impossible
     
  11. Brian1954

    Brian1954 Senior Member

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    Your Autel AP2500E scan tool is probably better than your friends scan tool for the Prius. The Autel AP2500E is capable of reading the freeze frame data for the P0AA6 trouble code. Within the freeze data, will be the subcode.

    Have you downloaded and read the user manual for the scanner? When you run a scan of the car with the AP2500E, you can choose to run three different scans, Basic Scan, Custom Scan, or Full Scan. You want to run the full scan. You need to learn how to use the Autel scan tool that you bought.

    Edit: Look at post #40 in this thread, https://priuschat.com/index.php?posts/3479277 . Click on the link near the end of that post and open the video. He is doing a Full Scan of his Prius using the Autel AP2500E. Notice all the different systems (ECUs) that are being scanned. Your scan process should be similar.
     
    #31 Brian1954, Feb 9, 2025 at 7:41 PM
    Last edited: Feb 9, 2025 at 8:33 PM
  12. dolj

    dolj Senior Member

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    In addition to what Brian said about your scantool, I'll make these observations about the codes you posted.
    These code are from the TPMS and mean that there is no signal coming from the wheel pressure transmitter IDs 2, 3, and 4, respectively. The fix for this (if you care) is to replace those valve stems that contain the transmitters. This is of no significance right now and can be ignored.
    This is not a valid code, most likely the software does not know the correct to translate to display. It could be P3000 which is reasonably generic.
    If you read the codes inside or at night, you can ignore this code. It simply means that there was no bright sunlight shining on the light sensor on the passenger side (right-side) dash. Of course, if you took the reading in bright sunlight then there is something to look at here. FYI, this is not really a true code in the normal understanding of DTCs. It really performs a binary switch function and operates in real time if you monitor the PID with your scantool. Its purpose is to feed into the A/C system and boost cooling if the car is in direct sunlight.
    This is your real problem. One of four parts of the hybrid system (see diagram in post #29) has a high voltage electrical system isolation fault and not necessarily from the hybrid vehicle battery. The INF code (611, 612, 613, or 614) will pinpoint the sub-system area. Also, post #29 mentions a method to pinpoint the area without needing a scantool.
     
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  13. ChapmanF

    ChapmanF Senior Member

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    There isn't really anything software needs to know about a code before displaying it. The sixteen bits received are displayed as a five-character code using one simple algorithm for all codes. The last three places are just the lowest twelve bits shown as hexdigits, and the first two places come from the top four bits, like this:

    [​IMG]

    That means it's pretty rare for any scan app to actually mess up displaying codes themselves. Not that it's never happened, but it can only mean a pretty basic programming mistake in the software.

    That's just for the code itself, of course. If a tool is also going to display fortune cookies like "malfunction in HV system" for the codes it displays, then it does need to contain the list of those.

    P0000 is exactly the code you would show for sixteen bits all zero. It happens that all the P0 codes are SAE-defined and SAE's list starts with P0001, so in that sense P0000 isn't a valid code, but whatever problem led to its being displayed might be some other kind. I could imagine a scan tool getting an incomplete or garbled reply packet and trying to decode/display a zero-filled buffer without first checking the packet was received complete and error-free.