08 prius keep dying

Discussion in 'Gen 2 Prius Main Forum' started by richard203, Oct 16, 2025.

  1. richard203

    richard203 Member

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    just an update. I replaced the inverter pump today and drive the car and died again checked the code and it gives a P3102 Transmission Control ECU Code

    IMG_7852.jpeg
     
    #21 richard203, Nov 14, 2025 at 8:41 PM
    Last edited: Nov 14, 2025 at 9:03 PM
  2. dolj

    dolj Senior Member

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    There are seven INF codes for that DTC: 524, 525, 581, 582, 597, 598, and 599.

    Clicking on the snowflake icon right there on the left of your screen will tell you which INF code you have. Knowing the code helps to follow the correct diagnostic procedure.

    With two of the INF codes, the car is impossible to drive. The other five talk about the shift position being fixed or not, and the car being impossible to drive or not is dependent on that position being fixed or not.

    There is also mention of communication problems between the BEAN and the transmission control ECU assembly.

    In short there are too many possibilities without the INF code.

    It is not clear from the context whether the meaning of the word fixed means corrected/repaired or stuck in place.
     
  3. richard203

    richard203 Member

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    here’s the INF Code - 3102-525

    IMG_7853.png
     
  4. dolj

    dolj Senior Member

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    DTC P3102/525 indicates a malfunction in the transmission control ECU. This code is often associated with issues in the park lock system or the park lock actuator motor. It can lead to problems with shifting gears or engaging the park position.

    For detailed repair procedures, refer to the official Toyota repair manual for the 2008 Prius. This manual will provide specific instructions, wiring diagrams, and troubleshooting steps tailored to your vehicle.

    Toyota Service Information and Where To Find It.
     
  5. richard203

    richard203 Member

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    what if the cars goes into gears and can put in park. do that mean the park lock system is good?

    I looked the code up it shows that it's either wiring or ecu issue

    - Wire Harness /Connector
    - Transmission Control ECU Assembly
    - HV control ECU
    - Power Source Control ECU
     
    #25 richard203, Nov 14, 2025 at 11:04 PM
    Last edited: Nov 15, 2025 at 1:34 AM
  6. dolj

    dolj Senior Member

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    The detection condition is: Transmission control ECU IG OFF command malfunction, so it is reasonable to be looking at the wiring.

    In another place in the manual, for the detection condition, it states: Transmission control ECU IG OFF command malfunction and names these trouble areas:
    - Wire harness or connector
    - Transmission control ECU assembly
    - Hybrid Vehicle control ECU
    - Power source control ECU

    Given the broad scope, I would think following the diagnostic steps for P3102-525.
     
  7. richard203

    richard203 Member

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    is there a link to follow the step?
     
  8. Brian1954

    Brian1954 Senior Member

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    The link to obtain access to the Toyota repair manual is in post #24.
     
  9. Tombukt2

    Tombukt2 Senior Member

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    I could copy and send direct only it's long I think . Are you in a mouse area where they mite be in car ? Other than that look into spare computer modules mentioned . And they're a pain to swap. Take the two or three computers from a known good car say w dead batteries or brake actuator down . I have several sets here .
     
  10. richard203

    richard203 Member

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    Isn’t that show the link to Toyota website u need to pay for it right?
     
  11. richard203

    richard203 Member

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    um the mouse part might be hard to say. Lol where can you sent me directly and how much you selling the computer?
     
  12. Tombukt2

    Tombukt2 Senior Member

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    I don't know man you pay the postage you can have them whatever. They not that heavy but they odd shaped I think
     
  13. Tombukt2

    Tombukt2 Senior Member

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    I'm in Central North Carolina.. I would just send the copies from the manual to like your email or your phone if it can take that kind of hit
     
  14. Tombukt2

    Tombukt2 Senior Member

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    Yes they do that here they're are folks with the whole manual 9nline too. I would hate to think anybody would invoke copyright infringement policies on folks reading about a 20 yr old no classic car etc . Wouldn't be any real money in that
     
  15. Brian1954

    Brian1954 Senior Member

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    Correct. You create an account and pay for two day access to get the repair manual section for the trouble code that you have. Then, follow the steps in the manual.
     
  16. Hayslayer

    Hayslayer Active Member

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    The good thing is if you decide to just change that ecu, it can be had for 10-20 bucks at most salvage yards, is mounted under the glovebox and takes about 5 minutes to replace. Pop off the plastic trim cover, remove 2 bolts and one plug, if I remember right.