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ABS issue, Beeping and many dash lights

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Sarah Brady, Aug 17, 2023.

  1. Sarah Brady

    Sarah Brady New Member

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    Hey Y’all, I have been dealing with my problematic 2008 Toyota Prius (176k miles) for a few months now. While driving out of town a collection of lights turned on along with a beep that soon shut off. The lights that came on were Red Triangle, ABS, emergency brake, VSC, ((!)). I parked the car and the next time I turned it on the lights were off and the driving was normal.
    I’ve taken it to MANY mechanics all who are stumped as to what is wrong. I did recently change my catalytic converter to an aftermarket product. I am unsure if that has anything to do with my Christmas tree plus beep issue.
    The beep is inconsistent and doesn’t seem to have a pattern. I have reset via unplugging both batteries then reconnecting, and a cheap code reader plus a mechanic reset the computer multiple times. After a reset the car will drive normal for about 30-45min then check engine light comes on. After 10-15 more min the ABS, VSC, and Red triangle come on, the beep will come on as well but will shut off and come back intermittently. I can’t seem to track the pattern. Also when the beep occurs my cold air stops, not the blower just the cold. I also want to note that my brakes are stiff and when the beep occurs the brakes are very stiff along with not being able to shift into reverse.
    I’ve been told my EV battery is throwing false codes so I haven’t gotten a clear code reading. I’m hesitant to change the EV battery in the case that I need an actuator or brake bleed.
    I’ve been told I need either a new speed sensor, abs module, abs actuator, brake bleed, EV battery, but never narrowed down.
    Please disregard comments telling me to trade it in or take to a dealership, I am aware of those options and am looking more for how to maintain my old girl plus I’m still paying on this vehicle.
    upload_2023-8-17_16-8-53.jpeg upload_2023-8-17_16-9-8.jpeg upload_2023-8-17_16-11-57.jpeg upload_2023-8-17_16-11-40.jpeg upload_2023-8-17_16-11-19.jpeg
     
  2. Sarah Brady

    Sarah Brady New Member

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    I conducted the blink test and found the codes, ECB 41, ABS 42, VSC 45.
     
  3. JC91006

    JC91006 Senior Member

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    can you get the car ready and open the inverter coolant reservoir cap and see if the pump is working? If it's working properly, the fluid will have a boiling effect to it, when the pump is pumping fluid. If it's not working properly, then the fluid will not have much movement
     
  4. Sarah Brady

    Sarah Brady New Member

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    I will do that next thank you! I just tested my 12V battery and the results were not promising.
    Power button once upload_2023-8-17_20-55-7.jpeg
    Then power button again
    upload_2023-8-17_20-55-44.jpeg
    Car fully on
    upload_2023-8-17_20-56-8.jpeg
     
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    To start, I'm sorry to hear you're having these problems and I understand 100% about wanting to keep the car going. At this time, the code reader you're using is not adequate and is likely directing you on a wild goose chase.

    The P1121 code has nothing to do with the throttle, it is for the coolant control valve position sensor. The coolant control valve merely controls the flow direction of engine coolant into auxiliary systems. I've driven several Gen 2s with this code and none have had engine overheating problems, so I would say you are not in any immediate danger due to this code, but it should be repaired when reasonable. (assuming the code number itself is being read correctly).

    P2238 is for the Air fuel ratio sensor, which is the upper sensor mounted in the exhaust header, not the O2 sensor mounted downstream at the catalytic converters.

    It's very likely your reader is not capable of reading the specialty codes, so is showing nothing for your brake system, even though it's probably thrown codes. Your brake symptoms tend to lean toward an actuator issue. I've never seen a P1121 or 2238 cause secondary problems with brakes, but maybe it's possible. The P2238 also lists the ecm and integration relay as potential sources of the code, not only the sensor itself. Perhaps they have some overlap with the braking system.
     
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  6. Sarah Brady

    Sarah Brady New Member

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    Thank you for sharing your knowledge. I knew that the code reader I bought would only tell me a general guess. I really bought it to clear the codes hoping that would get it driving a little longer. FYI that didn't work. I'm thinking there are likely multiple issues I'm dealing with, just trying to determine if changing the 12V is the main issue or another ABS-specific problem. Hopefully not more along with bad voltage.

    I just took a look under the hood, and unfortunately, the fluid was not moving.
     
    #6 Sarah Brady, Aug 17, 2023
    Last edited by a moderator: Aug 18, 2023
  7. ChapmanF

    ChapmanF Senior Member

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    The brake code was in post #2. ECB 41 is C1241, a complaint about the voltage reaching the brake system.

    (ABS 42 and VSC 45 both only mean "hey, go look at the ECB code".)
     
  8. Sarah Brady

    Sarah Brady New Member

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    Thank you, Chapman! After I figured out the blinking system I searched the chat to find that yep C1241 is my magic code!

    Also, I'm concluding that I will need a new inverter cooling pump due to the liquid reservoir being still. It doesn't look too difficult to manage.
     
  9. JC91006

    JC91006 Senior Member

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    Yes the 12v battery should be the first replacement before you do anything else. The battery could be the culprit giving out all these strange errors.

    10.7v under a small load is pretty bad
     
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  10. dolj

    dolj Senior Member

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    C1241 is a particularly difficult to diagnose and fix. It seems even a lot of Toyota "master technicians" were not paying enough attention in class and can fail to come up with answers.

    Although the 12 V battery is not a usual culprit with this code, be aware that sometimes the DC/DC converter is shut down and so the 12 V battery provides the power for the car until the 12 V battery voltage gets very low - somewhere below 10 V Therefore, you should check the 12 V battery (and for good measure the terminal connections at the battery and ground connection to the body that they are clean (free of corrosion) and tight) is not currently low. If it is lower than 12.3 V get it on a charger to fully charge it before doing any further diagnostics.

    Voltages within or received at the ECU that set this code are much lower than 10 V – 8.9 V, 8.4 V, 5.3 V, 5 V, 4.9 V, or 4.7 V.

    If you can get a scan done by someone with a good enough scanner that can get the DETAIL code (or sometimes called INF code) that goes along with the base C1241, that can help. Possible values for the INF code are 81, 82, 83, and 84. Getting the freeze frame data (FFD) would be useful too.

    Possible areas that could be involved and can be checked are:
    • ABS NO. 1 relay
    • ABS NO. 2 relay
    • Harness and connector - Skid control power supply circuit
    • Brake control power supply assembly (This is the black box in the back under the floorboard next to the 12 V Battery.)
    • Hybrid control system
    If you want more information about troubleshooting this code, I've attached the repair manual troubleshooting procedure.

    If you have any questions, please ask.

    Good luck.
     

    Attached Files:

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  11. dolj

    dolj Senior Member

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    The battery could be damaged, but it is not necessarily a write-off. Charge and test first before condemning it.
    The inverter getting too hot and shutting down the DC/DC converter is a definite possibility and in turn setting C1241.

    Change the inverter coolant pump with a new OEM one and retest.
     
  12. JC91006

    JC91006 Senior Member

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    The drop from the initial small load at 11.9v to 10.7v is pretty significant (with nothing really on). Testing or not, it most likely won't be any good.
     
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  13. Sarah Brady

    Sarah Brady New Member

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    I just ordered a new one and will install it once it arrives. I am new to DIY on cars, do I need to reset anything once the new pump is installed?
     
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  14. dolj

    dolj Senior Member

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    Sorry, I don't see where that was mentioned. But maybe yeah, if that is so.

    [EDIT] Never mind JC, I just saw the images of the battery test. I missed that post altogether.
     
    #14 dolj, Aug 18, 2023
    Last edited: Aug 18, 2023
  15. dolj

    dolj Senior Member

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    Nope, just make sure all air is bled out of the system. Judicious use of hose clamps can make sure very little air gets in and coolant is lost.
     
  16. Sarah Brady

    Sarah Brady New Member

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    I will most likely change the 12V to a new one. I have driven the car for over a year and have put many miles on the old girl. I am a pizza delivery driver so I drive over 400 miles a week. Replacing the battery is a no biggie for a long-time driver. Thank you all for the help. I will continue to update as I replace and continue further diagnostics.
     
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  17. Sarah Brady

    Sarah Brady New Member

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    Already ordered the clamps. Thanks! Looking forward to learning a new replacement process.
     
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  18. theory816

    theory816 Junior Member

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    Generally, Toyota Hybrids develop an ABS module problem at this mileage. The ABS module uses an accumulator and a small DC motor to power the braking system/hybrid regen. They both degrade over time. The small DC motor has brushings that can be replaced but you'd have to have the right brushes which are hard to find. DIY this incorrectly and it'll cause electrical problems. The accumulator degrades and can't hold pressure.

    Generally, I would specifically replace the broken part, but because the ABS module consist of several parts that are degrading, one should bite the bullet and just replace the entire module.

    Scout ebay for some refurbished parts but it may be difficult to find parts with are in good condition and for a good price. The good news is that Prius parts are smaller and easier to work with compared to something on an SUV hybrid.

    All that said, check the DTCs to find what the issue is first to see if it isn't something else.
     
    #18 theory816, Aug 18, 2023
    Last edited: Aug 18, 2023
  19. dolj

    dolj Senior Member

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    She has and the codes don't implicate the ABS, for now.
     
  20. Brian1954

    Brian1954 Active Member

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    She needs a better scantool to read all the trouble codes.

    Posted via the PriusChat mobile app.