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TSB (NiMH only): Reduced power when accelerating from a stop

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by Elektroingenieur, Oct 21, 2017.

  1. Elektroingenieur

    Elektroingenieur Senior Member

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    On July 27, Toyota issued Service Bulletin T-SB-0241-17, “Reduced Power When Accelerating From a Stop,” applicable to 2016 and 2017 model year Prius cars sold in the U.S. with NiMH batteries (ZVW50), but only if, “after repeated driving on long downhill slopes,” they have either of two symptoms: a reduction in power “when accelerating from a stop, or from extremely low speeds,” or a battery monitor that “continually shows one bar.”

    The countermeasure is a software update for the Hybrid Vehicle Control ECU, in which the “logic has been modified to reduce the possibility of these conditions.” With the new software, the HV ECU part number changes from 89981-47550, 89981-47551, or 89981-47552 to 89981-47553, but no parts are physically replaced. Dealers should affix an Authorized Modifications Label (00451-00001-LBL) under the hood after reflashing the ECU.

    In the U.S., the update is covered by the Toyota Hybrid Vehicle System Component Warranty (96 months or 100,000 miles), but only if the symptoms in the bulletin are present and the vehicle was produced before the relevant production change, i.e., it has a VIN earlier than JTDKBRFU#H3035100 (Tsutsumi Line 1) or JTDKBRFU#H3544587 (Tsutsumi Line 2).

    At this writing, the bulletin appears to be available only by subscription to techinfo.toyota.com; I’m not aware of a free source. The calibration files are also available to download there, but only with a Professional Diagnostic subscription (from $55).

    Considering the real possibility of a damaged ECU if the update fails, however, I’d advise against a do-it-yourself update, unless you (a) are prepared to follow the instructions in Service Bulletin T-SB-0134-16, “Techstream ECU Flash Reprogramming Procedure,” to the letter, including the use of a genuine Mongoose or other approved vehicle interface module, plus a GR8 Battery Diagnostic Station to maintain the 13.5-volt power supply, and (b) could shrug off the cost of replacing the HV ECU (list price $312.50) if something goes wrong.

    For reference, here are the old and new calibration IDs (software version numbers) listed in the bulletin:

    Previous MAIN Calibration Previous SUB Calibration New MAIN Calibration New SUB Calibration
    1 899834751000 899854702000 899834751300 899854702200
    2 899834760000 899854702000 899834751300 899854702200
    3 899834751100 899854702100 899834751300 899854702200
    4 899834751200 899854702100 899834751300 899854702200
    5 899834760100 899854702100 899834751300 899854702200
    6 899834760200 899854702100 899834751300 899854702200
    7 899834734000 899854701000 899834734300 899854701200
    8 899834734100 899854701100 899834734300 899854701200
    9 899834734200 899854701100 899834734300 899854701200
    10 899834757000 899854707000 899834734300 899854701200
    11 899834757100 899854707100 899834734300 899854701200
    12 899834757200 899854707100 899834734300 899854701200

     
  2. Prodigyplace

    Prodigyplace Senior Member

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    Do you need to be experiencing symptoms for the TSB to apply?
    My car appears to be in the affected range.
     
  3. bisco

    bisco cookie crumbler

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    'only if the symptoms in the bulletin are present, and the vehicle was produced before the relevant production change'.

    see the third paragraph for applicable vin #'s.
     
  4. RCO

    RCO Senior Member

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    Nothing beats me from the green light when I'm 'in the groove'
    D'ya think I'm turning into a boy-racer as a sort of last hurrah? :cool:
    Can't get the peak of my cap to stay at the back tho! It keeps swivelling around to the front.
     
  5. Elektroingenieur

    Elektroingenieur Senior Member

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    In principle, yes; if you’ve never noticed the problem, there is no need for the update.

    In practice, probably not: if you visit a Toyota dealer and say something like, “After descending the Angeles Crest Highway [or whatever long, steep grade might be well-known in your area], the car wouldn’t accelerate very well,” and mention the bulletin number, I wouldn’t expect them to pass up the chance to satisfy you and bill Toyota for 0.4 hours of warranty labor by doing the update, especially if you’re also paying them for other maintenance in the same visit.
     
  6. Prodigyplace

    Prodigyplace Senior Member

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    @Tideland Prius I reported for a sticky. Perhaps you can add this information to your TSB sticky.
     
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  7. kithmo

    kithmo Couch Potato

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    No TSBs reported on the UK Toyota recall checker for mine. (y)
     
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  8. Prodigyplace

    Prodigyplace Senior Member

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    Is there an expiry date on this TSB?

    BTW, my local dealer is so bad they did not even get my Prius sale. I drove 150 miles to save more from as knowledgeable edealer. I will not be spending any more than needed for them to perform service. They did my 5K mile check but I changed the oil & filter myself at 10K.
     
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  9. Elektroingenieur

    Elektroingenieur Senior Member

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    The bulletin I described above is only for the U.S. market. I checked the list of Prius (ZVW50) technical service bulletins on toyota-tech.eu and didn’t see anything listed with a similar title.

    This is only a service bulletin, not a campaign or recall, so dealers are expected to apply the countermeasure only after a vehicle is presented for repair of the condition described in the bulletin. Toyota and its dealers are unlikely to contact owners proactively about service bulletins; indeed, Toyota Warranty Policy 5.21, “Warranty Solicitation,” prohibits dealers in the U.S. from making such contacts, unless there is a campaign or recall.
    There isn’t one listed in the bulletin.
     
  10. Prodigyplace

    Prodigyplace Senior Member

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    There is an implied expiry of 96 months or 100K miles.
     
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  11. dslomer64

    dslomer64 Member

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    My Prius 4 has VIN JTFK A RFU4H 30*****, so I guess it was produced before either "VIN date". But does "Line 1 or 2" mean, as someone already stated, only Prius 1 and 2 have been identified as candidates for j update? If so, I guess I'm not a candidate.

    Anyway, I'm not having any symptoms.

    However, I regularly get a message upon starting a cold (and maybe warmed up) engine. It's something like "Hybrid system not ready. Please put foot on brake before shifting". (I'll write it down next time I see it.)

    I'm reasonably sure I'm rushing the startup procedure, because I cannot remember ever having to do anything over. Then again, I doubt I'd notice, since the process is now habitual--no thought occurring.

    In any event, I always continue to back up or go forward with no further messages and no problems driving. In other words, I think I go through the steps correctly but faster than the software can process them, leading to bogus messages (or maybe I AM actually "doing it wrong").

    Whatever, starting NOW, I will pause between actions and wait (and look) for possible valid messages to appear. If any do, I'll definitely record anything seen as amiss by the software and get back to y'all.
     
    #11 dslomer64, Aug 27, 2018
    Last edited: Aug 28, 2018
  12. Prodigyplace

    Prodigyplace Senior Member

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    Line 1 and Line 2 refer to two different manufacturing production lines not to the resulting products.
    In the US only trims One and Two have this battery. ECO and higher have a different battery chemistry.

    You must have your foot on the brake when shifting into gear. If you have your foot on the brake and still get this message perhaps the brake pedal switch is defective. I believe @alanclarkeau in Australia had a similar issue and got the switch replaced under warranty.
     
    #12 Prodigyplace, Aug 28, 2018
    Last edited: Aug 28, 2018
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  13. Elektroingenieur

    Elektroingenieur Senior Member

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  14. PMe

    PMe Junior Member

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    I think this message appears when the 12V battery voltage is getting too low. Then I assume this has been resolved meanwhile (can you confirm?), but good for others to know. I think this is a safety message ensuring the car will not drive unintentionally when the ICE starts and P-mode(?) is less reliable due to reduced auxiliary battery voltage.
     
  15. Zardoz

    Zardoz Member

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    Gee my car is in this range as well. I complained to Toyota and got the standard "could not duplicate" response. I will go back with the TSP number as I have no "mod" sticker under the hood.
     
  16. Jburner

    Jburner Member

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    I have a Four. How do I find out what battery chemistry is present
     
  17. Elektroingenieur

    Elektroingenieur Senior Member

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    For model years 2016 and later, the Four grade has a Li-ion battery. You can confirm this by looking at the certification label inside the left front door (the driver’s door, on U.S. vehicles), which will have a model code that begins with with “ZVW51.”
     
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