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Mysterious Engine Problems

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Chris figgo, Dec 2, 2021.

  1. Chris figgo

    Chris figgo New Member

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    I am absolutely dumbfounded. Just the other day I was driving on my normal way home and the friendly of’ triangle popped up (along with the (!) and VSC warning light but no check engine)! After like 20 minutes it went off, but now my Prius is driving different. When I accelerate it’s normal but when I coast I can constantly hear a rubbing/rumbling sound which is most apparent and loud when I brake. The car feels like it’s stuck in B mode for sure. Any advice on what this could be. I have a 2006 Prius with 197000 miles (almost at that 200k!) 293F6834-F8DE-4F58-857B-7F0ED0EB60D6.jpeg
     
  2. PriusCamper

    PriusCamper Senior Member

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    Buy one of these and keep it in your glovebox: Hybrid battery diagnostic and repair tool for Toyota and Lexus

    Whenever the triangle comes on you can use Dr. Prius app on your phone to read the error codes and clear the triangle and keep driving...

    Once you know the error codes we can give you a range of repair options depending on what you can afford....

    While waiting for the device to arrive you can disconnect your 12v battery for a few minutes to clear the red triangle. How long it takes to come back on will define how urgent the problem is.
     
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  3. SFO

    SFO Senior Member

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    While waiting for your OBD2 bluetooth/wifi adapter that was kindly mentioned by @PriusCamper , you might try retrieving the stored OBD2 codes (DTCs) by visiting one of the auto part chain stores (autozone, pepboys, carquest, AAP, o'reillys, etc) and asking for a free OBD2 scan of your vehicle. Be sure to try multiple locations even within the same chain, as not all chains/locations will have a toyota hybrid compatible OBD2 scanner, and may not be able to retrieve the stored codes. Once recorded, please post them here for additional guidance.
     
  4. ChapmanF

    ChapmanF Senior Member

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    Even before going to such a store, you could get the codes from the brake ECU (the reasons for the (!) and VSC lights) and probably even the TPMS ECU, using the jumper wire and blink-counting method. Won't work for the HV ECU so you will still be wondering about the codes behind the master warning triangle until there is a code reader handy.

    But because the ECUs talk to each other, often even finding out what the codes are in the brake ECU will give a hint or two about the codes elsewhere.
     
  5. edthefox5

    edthefox5 Senior Member

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    Hybrid battery has failed its in limp mode.

    Use the search forum link up top and search

    hybrid battery

    and read the hundreds of posts about failed hybrid battery we have all been through.
     
  6. ChapmanF

    ChapmanF Senior Member

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    And if you have any time left, you can read the trouble codes and see if that's what's wrong with your car.
     
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  7. TMR-JWAP

    TMR-JWAP Senior Member

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    I was driving on my normal way home and the friendly of’ triangle popped up (along with the (!) and VSC warning light but no check engine)! After like 20 minutes it went off,

    The above symptoms are 100% not indicative of a P0A80 (replace hybrid battery) code. The triangle of death does not just "turn off" 20 minutes later for an HV battery failure/code. But it might for an over temp in the cooling system or a glitch in the brake system.

    When I accelerate it’s normal but when I coast I can constantly hear a rubbing/rumbling sound which is most apparent and loud when I brake. The car feels like it’s stuck in B mode for sure.

    That pretty much eliminates being in limp mode.


    Best advice given was to get the codes read by a Prius speaking code reader.
     
    #7 TMR-JWAP, Dec 6, 2021
    Last edited: Dec 6, 2021
  8. Chris figgo

    Chris figgo New Member

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    So, its been a while, but I finally got my codes. Cost me a cool 160$ from Toyota. They said that my transaxel is going bad. The car was driving but now refuses to get ready. The codes they found were
    p0a2b
    p0a2c
    p3000
     
  9. Chris figgo

    Chris figgo New Member

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    Seems like you hit the nail on the head! The codes seem to indicate that’s the case :(
     
  10. Chris figgo

    Chris figgo New Member

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    Would it be worth disconnecting my battery to dry to get the car to enter into “ready? Currently the car starts (the electronic components), but does not go into ready, my guess is because of the codes I mentioned in my earlier post.
     
  11. ChapmanF

    ChapmanF Senior Member

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    Those codes are about a temperature sensor for MG2 in the tranny. There are wires from the sensor to the ECU. There are minor things worth checking before condemning the whole transaxle.
     
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  12. PriusCamper

    PriusCamper Senior Member

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    Yes... The disconnection of 12v will clear the codes until the car notices them again...
     
  13. TMR-JWAP

    TMR-JWAP Senior Member

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    P0A2B=Drive Motor A temperature sensor circuit range/performance=motor temperature sensor #2 performance problem=possible trouble area is hybrid vehicle motor

    P0A2C=Drive Motor A temperature sensor circuit low=Ground short in motor temperature sensor #1 circuit=possible trouble areas are hybrid vehicle motor, wire harness or connector, HV control ecu

    Sounds like I would follow post 11 to start and look to see if the sensor circuit has a ground.

    There are links in the forum for the online repair manual. It will provide the DTC guide for troubleshooting the code.

    The link below will take you to a post that has the service manual link

    help (code p0A1d) | PriusChat
     
  14. SFO

    SFO Senior Member

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    These were not taken from the most recent repair manual, but will give you a general idea.

    Here is the workup for DTC P0A2B with INFs 248 and 250 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/21bpm/0a2b248.pdf

    Here is the workup for DTC P0A2C with INF 247 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/21bpm/0a2c247.pdf

    Notice how each of the above DTCs have two (2) related INFs (aka subcodes), though not that helpful with these old workups, knowing the INF for an associated DTC may help save on labor, parts or unnecessary expense. Techstream (the same diagnostic software that the dealership technicians used, and then charged you 160 for their expert advice) can retrieve the three (3) digit INFs, if they exist for a particular DTC.

    Here is the workup for DTC P3000 with INFs 123, 125, 603 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/21bpm/3000123.pdf

    Here is the workup for DTC P3000 with INF 388 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/21bpm/3000388.pdf

    Here is the workup for DTC P3000 with INF 389 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Prius%20Service%20Manuals%202004/%E4%BF%AE%E7%90%86%E6%89%8B%E5%86%8C/04pruisr/05/21bpm/3000389.pdf

    Did the dealer include any 3 digits INFs for the above DTCs?

    Which part of CA are you near, maybe another member can offer help.

    These last two questions below are for a data point to see if there is a pattern for failures.

    Have you ever checked, or changed the ATF-WS in the transaxle assembly?

    Do you live in a mountainous area, or find yourself depleting the HV battery state of charge while climbing hills at speed?