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Transmission problems with Lexus ES?



  • There is another ES here in town that has written 'I hate my Lexus' on the windows.

    I may actually try that myself....

    Do you really want a solution to your problem or want to post the same tiresome tirade over and over again. Obviously, you are not pleased with the car. How many times do we have to listen to that same drivel. Why don't you just sell the car and be through with it ? Your success in arbitration or lemon law probably won't be that good. JUST SELL THE CAR. PROBLEM SOLVED.
  • scoti1scoti1 Posts: 676

    First, let me tell you that I do not own a hesitating Toyota or Lexus. I own a pretty responsive Toyota Sequoia, but I have experienced the hesitation as a passenger and have family affected by the problem. That said, I wanted to comment on your experience of being able to replicate the problem in every Lexus you have driven. This may be your experience, but complicating matters, is that I don't think it is the experience of everyone. An interesting experiment would be for you to find someone with the same model year who does not experience the hesitation and trade out cars and see what happens. Have you had others drive your car? Do they feel the hesitation?

    p.s. shepali, after reading the previous post, it appears that some do not like what you have to say. This is a problems forum and you have every right to express your opinion without someone calling what you write "drivel"-- getting a bit personal IMHO. Anyway, just wanted to say I appreciate your input and the light you have shedded on the issue.
  • wwestwwest Posts: 10,706
    DBW is NOT the problem.

    Yes, the DBW system firmware has an acceleration delay incorporated but that is there to protect the drive train, give the downshifted transaxle clutches time to fully and firmly seat before the engine starts producing tons of torque.

    Were the transaxle not so quick to upshift it might still be in the proper gear for acceleration and the delay would thus be unnecessary.
  • user777user777 Posts: 3,341
    the problem with that line of reasoning would be it would affect the majority of owners in a quite perceptable and perdictable manner. but that doesn't appear to be the case.

    i am still holding onto a HW non-linearity theory (either pedal actuation or sensing, or Trottle body actuation or sensing) complicated by the learning software.

    however, i'm also believing that we are talking about some different phenomenon here (lag for different reasons or gear hunting, or shift shock).
  • I wanted to comment on your experience of being able to replicate the problem in every Lexus you have driven. This may be your experience, but complicating matters, is that I don't think it is the experience of everyone.

    So, are you saying that other people that DO experience the problem, DO NOT experience it in every car they drive? I haven't heard anyone confirm or deny that, but may have missed it. I did see the guy who said he could get anyone's car to do this - some people didn't believe him - but I actually think that I could as well.

    An interesting experiment would be for you to find someone with the same model year who does not experience the hesitation and trade out cars and see what happens. Have you had others drive your car? Do they feel the hesitation?

    I am in the process of trying to get in touch with someone I know that does have the same model year car as me, to maybe try this experiment (if in fact she isn't experiencing the same symptoms) - but no, to date I have not. But, ALL of the ES loaner cars I have driven (3, I think) have exhibited the same symptoms, albeit in differing intensity - and I have to assume that other people don't have the problem in those cars.

    Other people that drive my car do experience the hesitation - that would include my husband, the service people at the local dealer, and the Lexus Mfr Rep. And people that ride in my car notice it as well.

    The explanation I was given by the dealer to this phenomenon is that it has to do with the learning ECU module, and that the module takes about a week to learn new habits. So, if my husband drives my car only once or twice a week (which is the case), that the module would still be programmed for my 'driving style'.

    What that doesn't explain is why it doesn't take a week or so before I notice the symptoms. I mean, if that were true, and the loaner was driven by someone with 'Lexus approved' driving style, then I shouldn't experience the symptoms. So, that brings me back to - it must be SOMETHING I'm doing....but WHAT?????? :confuse:
  • OK wwest - I really like the input you're giving, but sometimes you confuse the heck out of me!!! Can you try 'plain english'? :D

    So, what really is DBW? I thought it was just an electronic communication to the engine, rather than a mechanical communication. But I must be missing something based on your comment. I would have thought that any acceleration delay would have been a software attribute - and therefore adjustable.

    And when you talk about the clutch and protection - again, I think software setting.

    Having said all that, I think that what you described is in fact some (or all?) of the problem. That delay you describe sounds a lot like what I am feeling when the so-called hesitation occurs.

    Here's an example - I'm driving around in a parking garage that goes up/down in circle, and each circle intersects with oncoming traffic. When I approach the intersection, I take my foot off of the gas pedal so that I can look both ways before I pull out to merge. I put my foot back on the gas pedal to pull out - but nothing happens. I keep pushing, instinctively, and then all of a sudden, the car figures out it needs to either downshift or actually engage into a gear (not sure how to tell the difference), and it 'jerks' or 'clunks' into gear, and 'lurches' forward throwing my body backwards into the seat. This then happens at each 'intersection' of each circle in the garage. Very annoying....

    But user777 has a point - if what you are describing is true (which it seems to make sense to me), then why don't other people notice it? :confuse:
  • wwestwwest Posts: 10,706
    My 2001 Porsche 911/996 C4 6-speed stick shift is DBW, no mechanical connection between the gas pedal and the throttle plate. The 911 probably has the purest form of DBW, the firmware that monitors the gas pedal position simply drives the throttle plate servomotor into whatever position is dictated by the gas pedal position.

    When I depress the gas pedal on the C4 the throttle plate follows in complete and total synchronization right up until the engine reaches the rev limiter. It is totally and completely my own personal responsibility to be in the proper gear ratio for the acceleration rate that I desire (no lugging the engine) and to coordinate the gas pedal position with the engaging of the clutch.

    The DBW firmware in the Toyotas in question is seemingly different in that it "knows" that if it allows the engine to develop torque BEFORE the transaxle has completed the downshifting into the "most" appropriate gear for the acceleration level you desire then early transaxle clutch failure would probably result.

    And therein is the "RUB".

    The Toyota engine/transaxle ECU DBW firmware has no method, other than the current roadspeed and the current gas pedal position, of "knowing" just what level of acceleration you really desire.

    The firmware controlling these transaxles has apparently been specifically designed to put you into the highest gear possible, 5th with lockup, or maybe even 4th with lockup, at the very earliest time possible.

    That means that any time you release the gas pedal even slightly, and certainly fully released, it will quickly upshift into the highest gear ratio that is reasonable given the current roadspeed.

    But now you suddenly change your mind and depress the gas pedal, possibly just after the firmware has begun the upshift sequence. So the ECU "asks" "just how serious is he/she?", there are at least two possible gear ratios for it to downshift into and given the edict of fuel economy FIRST unless that was a serious "punch" of the gas pedal it will always chose the most conservative gear ratio, say from 5th to 4th.

    In the meantime you have noticed the delay in initial acceleration and human nature dictates that your reaction is to depress the gas pedal just a tad more.

    Oops, says the ECU firmware, he/she really wants to accelerate more rapidly than I first thought! The ECU cannot cancel the previously commanded downshift into 4th, it must now wait for that to complete and then command a downshift into third.

    With each downshift taking on the order of a second or so you may find situations wherein the throttle plate does not react to the gas pedal position for 1 to 2 seconds.

    The above is only a theory of mine but seems to be validated by what I have learned about the transaxle in my 2001 AWD RX300 and the newer 5-speed transaxles.

    Also, there have been indications here and there on these forums that quick and firm, non-hesitant, applications of the gas pedal alleviates the delay symptom.

    My 2001 AWD RX300 exhibits much the same gear changing procedures as proposed by Sierra Research. My 2001 AWD RX300 does not have DBW so during the resultant downshifts the clutch surfaces must endure an unusual level of wear. That is very likely why the earlier RXes are showing a level of premature transaxle failures heretofore unheard of for Toyota vehicles.
  • Lexus ES330's having transmission problems

    there are 49 comments on this story with other owners explaining there transmission problems
  • user777user777 Posts: 3,341
    DBW = Drive By Wire, an architecture that replaces a cable linkage between the accelerator pedal and the throttle with an electrical connection which is not direct, but is transformed by the ECM (Engine Control Module). The ECM is capable of many tasks, including telling the TCM (Transmission Control Module) when to perform shifting of gears, and optimal fuel / air delivery to the engine to maximize economy amongst other tasks.

    One of those other tasks may be to derate the engine when another subsystem detects wheel spin, or the vehicle is beginning to yaw excessively.

    Not only does it open the door to better fuel economy, it is an integral part of coordinated automation for improved safety.
  • hylynerhylyner Posts: 216
    A couple of days ago I posted some suggestions on how this hesitation issue might become more enlightening.(One comment I made was the problem really hasn't been fully unpacked yet--still feel that way BTW!!)
    One of the ideas I posted was that perhaps the much sought after "fix" was already out there because there are a number of commercially available performance enhancing products which do exactly what many of you suggest should be done. My point was simply that the technology already exists.
    My ideas were quickly dismissed as worthless, meaningless, etc., by some, and the discussion soon returned to what I've come to regard as somewhat of a blamefest with little or no interest in solutions.
    So I said I wouldn't argue or defend with "ye of little faith" and would simply post any further ideas that I felt might be constructive or helpful in this neverendum search for whatever.
    So I googled "Car Buyers Remorse", and found literally thousands of informative articles on how pervasive that phenomenon is. I honestly believe that phenomenon is hard at work in these forums!! Wow, 78 percent of car buyers have remorse about their purchase!!
    From the googled info, I reached an important (IMO) conclusion--that is "An ounce of prevention is worth a pound of cure!!!" (Old, but very wise piece of advice)
    Here's what one of many articles says (relevant advice highlighted) about one good way to prevent disappointment:

    78% of Car Buyer's Suffer "Why Did I Ever Buy That? " Remorse
    Majority of Car Buyers Have Wanted to Return a Vehicle Within First Few Days of Purchase

    RICHMOND, Va., Feb. 1, 2006 -- A recent poll of almost 49,000 car shoppers conducted by CarMax, Inc. on the company's Web site shows that 78 percent of car purchasers have wished they could return a car within the first few days of buying it. Only 22 percent of respondents had never experienced buyer's remorse.

    When asked the question, "Have you ever wished you could return a car within the first few days of buying it?" visitors to answered:

    Answer Number of Respondents Percentage of Respondents

    Yes 38,421 78 percent

    No 10,553 22 percent

    "An easy way to prevent buyer's remorse is to check the seller's policy on returns or exchanges before purchase, much like you would if you were buying merchandise from a big box retailer," says Joe Kunkel, senior vice president of marketing and strategy for CarMax. "CarMax offers a five-day, or 250-mile, no-questions-asked, money-back guarantee. Traditional dealer policies overwhelmingly vary from no money-back or exchange policies at all to policies that only allow an exchange. This is just another piece of the car buying transaction where it pays to be fully informed before signing a purchase contract."
    CarMax is the nation's leading specialty retailer of used cars. Headquartered in Richmond, Va., CarMax currently operates 48 used car superstores in 22 markets. CarMax also operates 12 new car franchises.
  • Even though the car doesn't have a button to tell the transmission you want power or economy, the car does have a very nice shift lever.

    If you are reading this and you feel hesitation when you step on the gas pedal when driving around town, keep the transmission in position 4 when you are driving around town. You still get an occasional rough downshifts, but the hesitation issues will be much improved. You will notice a slight decrease in fuel economy.

    I go a step further and shift down to position 3 in any situation where I feel I might need instant power (like accelerating onto the highway) and I am travelling in that dreaded near 30mph speed.

    Once the car is above 45 mph, you can shift into D. When you drop below 45 mph, shift back into 4.

    This shifting around I do defeats the shift logic of the transmission since I am overriding it.

    If this is all too much for you (you really want a truly automatic transmission), sell the car and try a different brand. General Motors gets criticized for mainly selling vehicles with 4 speed automatic transmissions because they are not that "advanced;" but you are now aware of the downside (for a minority of drivers) of these "advanced" transmissions.
  • Wow! That was impressive! And, it makes total sense in relation to what I'm feeling/experiencing.

    Question is - now what? Is there any way for me and the car to adapt to each other? Or, am I destined to not have a car with this technology?

    And if the latter - how do I know when I'm evaluating a new car, whether it has this same technology? Cause right now, I am totally gun shy on buying a new car - for fear that I will make the same mistake again.....
  • Some of you guys seem to really understand this technology - and I really appreciate your input...

    Do any of you know if the Nissan Maxima uses this same technology? Or how I would find that out?

    Once I figure a way out of my ES, that's what I've been considering as a short-term replacement....until I can get my head on straight again about what I really want in a car...
  • hylynerhylyner Posts: 216
    I think I said earlier "An ounce of prevention equals a pound of cure"
    Just a heads up 4U re your Maxima query. It does have the same technology, with similar complaints BTW.
    An excerpt from the Maxima board---I think you'll agree it sounds vaguely familiar...

    "The problem you are having seems awfully akin to the surging we've been complaining about on the Maxima 5 speed. In our case, it's not the transmission, it is the ECU causing the problem. When you are using very light throttle, the ECU tends to take control from you making it hard to drive smoothly. This can give you whiplash trying to drive in 1st gear at parking lot speeds and causes car to surge a bit at highway speeds with the cruise control on (and some report much worse behavior going down long downgrades at highway speeds). The torque converter on the automatic will normally mask the problem but with the lockup clutch bypassing the torque converter engaged, you can probably feel it on the automatic.

    Check out the first few posts about the 5 speed for a full description of the problem (note there is a TSB out for this problem as well). The TSB has been posted to the board."

    Shepali, make sure you're not going to require another "Hate My Car" message on your car window. Also, probably not a good idea to say anything about this at your arbitration as well. ;)
  • scoti1scoti1 Posts: 676
    I don't know about the Maxima. Whatever you get, take it for an extensive test drive.

    Also, find someone who has bought from the same dealership and see what they think about the customer service there and if they had any problems addressed under warranty. Nearly every new car I have purchased has had some warranty related issue and fortunately all were resolved satisfactorily, including probs with my current Sequoia, including a problem with a rotten egg smell that they corrected with a new cat. converter. It sounds like you aren't happy with the customer service you are getting from your Lexus dealer so you want to make sure you don't run into that again.
  • wwestwwest Posts: 10,706
    Is very often also the BLEEDING EDGE.

    Toyota has made it quite plain, publically, that they will be the early adopters of any new technology that results in improved fuel economy and lower emissions.

    Since Sierra Research is clearly a consulting resource for CARB Toyota has apparently decided to lead the "pack" yet again, still, by adopting these SRI "suggestions" before CARB manages to make them mandatory.

    Question: Has anyone having these hesitation problems ever experienced any diagnostic indications that the accelerator position sensor is faulty or was intermittent?

    I'm still not certain, by any means, that the fault doesn't lie, somehow, within the dual hall effect accelerator pedal position sensors.
  • user777user777 Posts: 3,341
    wwest - glad you remain open to the possibility of a hardware problem, potentially exacerbated by the software implementation. this would fit with the observations.

    personally i would not limit myself to the accelerator...there is a position encoder on the throttle body. ;)

    i think way back i suggested someone with a reproducable and acknowleged problem essentially beg for mercy at a dealership and suggest these components to be swapped...

    remember the "no guts no glory" post?

    ok - consider this as well, wonder if it's not a position encoding problem, but mechanical sticktion in the throttle body? woa. what a possibility.
  • wwestwwest Posts: 10,706
    No, the throttle valve is "sticking" at times I would expect it to do so, during "unexpected" downshifts, times when the transaxle clutches are likely not fully seated and thus there is a need to delay engine torque in order to "protect the drive train".

    Also the dual throttle position sensors and the throttle valve are driven by a common servomotor and were the sensor outputs not to "follow" the commanded movement of the servomotor that would be quickly detected and reported as a major component failure.

    On the other hand since your foot is the "servomotor" the accelerator pedal sensors have no method of cross-checking other than the validity between the two sensors themselves, which, according to the manual is done continually.

    If one of the two sensors was intermittent, occassionally gave a position reading not consistent with its opposite sensor then the ECU would undoubtedly consider that reading invalid and by default, failsafe, "report" the accelerator pedal to be in the "neutral" position.

    It would be anyone's guess as to how many valid readings, contiguously, it would then take for the system to consider the sensors to be giving valid readings again.

    I have no doubt that once an invalid accelerator pedal position reading occurs there would follow a period of defaulting to the pedal being at the neutral position.

    Begins to sound as if it could be the exact thing ocurring, huh?

    Think about this, the accelerator pedal sensor outputs are analog, and therefore must be "read" by the ECU via an A/D, analog to digital converter. Unless some sort of sample and hold circuit is used to trap both voltages absolutely simultaneously, the ECU first samples one sensor and then the other. In the normal scheme of things this occurs so very rapidly that for all intents and purposes the signals are sampled simultaneously.

    But suppose some highly important "other" function (VSC Yaw sensor??) just happens to interrupt the ECU A/D converter sampling/processing between the two samples. "Highly important" because "normal" interrupts would be locked at at this stage.

    In point of fact the industry standard CAN (Controller area network) handling the VSC/Trac/ABS, etc, communications is entirely separate from the Toyota propriatary BEAN (body electronic area network) handling everything else, including the engine/transaxle ECU communications.

    I could readily see that an input from the CAN system would be allowed to interrupt almost any process in the BEAN system.


    Some posters have stated that the symptom often occurs during a turn, a time when the VSC system might be highly active.
  • user777user777 Posts: 3,341
    i'm thinking, mechanical sticktion or binding may occur during one portion of possible radial travel (like the low end / near-zero for example).

    then again, there may be a non-linearity due to slop between the mechanicals and the encoder(s)...

    but you touch on another valid possibility, with all the integration and distributed subsystems, it's entirely possible a rouge subsystem is generating too much traffic, resulting in collisions, retransmits, and even missed parameter reception and/or time-slice "over-runs".
  • hylynerhylyner Posts: 216
    Please don't think this is presumptuous guys, but I'm wondering if this is the wrong forum for all this highly technical stuff. I thought that was why Wwesty's forum " Toyota/Lexus Transaxle Shift Delay" was created?
    I honestly think much of what you're talking about here is way over most participant's heads. Besides, it doesn't really leave much room for others to participate.
    Whaddya think? Any thoughts by Mr. Shiftright?
  • wwestwwest Posts: 10,706
    300 Gigabytes of disk drive storage for what, under $200? So I very much doubt that there isn't room here for anyone or everyone who wishes to participate, on topic, isn't "free" to do so...
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,588
    This forum is primarily for people who own Lexus ES-300s and are experiencing transmission problems of whatever kind.

    If you (or if the Lexus 300 owners) want a more technical discussion they should all be over in the "Shift Delay" discussion.

    So if you a)don't own a Lexus 300 and/or you want to discuss the technical aspects of Lexus transmissions, you should be there, not here.

    This discussion is intended mostly for people who don't particularly care what is causing the problem but want suggestions on how to get Lexus to fix it or how to arbitrate, etc. (service/consumer issues)

    So if you are posting highly technical stuff here you are in the wrong discussion, yes.

    thank you, and I hope that clarifies things.


    MODERATOR --Need help with anything? Click on my name!

  • user777user777 Posts: 3,341
    if you have a reproducable and acknowleged problem with hesitation in your Lexus ES300 series vehicle:

    suggest to your dealership they replace your throttle body assembly and road test the vehicle. if that doesn't work, suggest they replace your accelerator assembly and road test the vehicle.

    report success or failure for one or both procedures to mitigate the issue here in this forum or the other forum on "Shift Delay". everyone would benefit by the effort and report.

    i trust that if anyone had a problem following a previous post regarding "position encoding", "sticktion", "slop", "non-linearity", "time-slice overrun", etc, they'd either google the terms or ask. i don't presume people aren't able to follow a technical line of reasoning, but understand it may not be of interest to everyone.

    unfortunately NOONE is providing definitive information as to WHY the hesitation exists or does not. therefore, there is a great deal of speculation and theorizing on the matter...

    a few experiments have been suggested to narrow the problem down, some in a forum which has been marked read-only.

    with the two suggestions above, the experiments i have proposed now total at least three. the other involves the use of an OBD-II interface and laptop computer.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaPosts: 57,588
    thank you!

    MODERATOR --Need help with anything? Click on my name!

  • I like your suggestions, but I can't really do that at this point, because the dealer, the manufacturers rep, and now the manufacturer have all said that there is nothing further they can do to the car, and that the car is operating as designed (which, for the record, I do not accept and have told them so). Thus, I don't believe they would be willing to replace such parts at this point.

    And, although I would be open to the experiments - given that I have experienced these symptoms in ALL ES330's I have driven - I'm not too hopeful that replacing these parts would do any good, unless they replaced them with different brands/versions of those parts.

    On a side note - I don't mind all this technical talk, but I do not understand most of it. Having said that, I am starting to learn things from it. But, I do appreciate when you guys summarize into action items as you did in the reference post ;)
  • user777user777 Posts: 3,341
    shepali - you indicate you can replicate the behavior in ANY ES330 you can drive. please describe your driving style again, and the scenarios where you can get the vehicle to exhibit the hesitation? in this respect, hesitation is a noticeable delay in the vehicle accelerating after appropriate application of foot pressure on the throttle.

    it might be helpful to know if you are giving the vehicle just a little throttle or more.

    tell us specifically what you are noticing with respect to the RPMs changing as you apply the throttle in these scenarios.

    btw - do you live in an area where there is only one Lexus dealership? i ask because, even if the manufacturer's rep and your primary dealer rep aren't interested in trying anything else, another dealership just might, depending on how you approach them. again, even at your present dealership, you don't know if they are willing to try something else unless you ask (in the right way), and you have said they were working with you... hope you have all the things they did try documented.

    lastly, if there is any technical jargon i'm using that is throwing you, as advised by the host, we can discuss it in the shift delay forum.

    also know this - because you can repeatedly reproduce the hesitation (if it is a hesitation, not a hard shift for example), then you may be a candidate for the experiment proposed in the shift delay forum.
  • atoewsatoews Posts: 637
    I would suggest that before anyone else wastes a lot of time and energy on this problem, they read the last 3-4 years worth of posts on this thread!

    Poster after poster has beaten his or her head against the wall on this particular dead horse! Do a search on poster texas83, for example. He expended all kinds of energy on the problem, pursued the Lemon law and never received a satisfactory resolution to the issue. All he got was a replacement ES300 for his considerable efforts, and of course this did nothing to fix the problem.

    Yes, it takes time and energy to read old posts, but not nearly as much time and effort as trying to get Lexus/Toyota to fix a problem that they do not even see as a problem!

    These posts provide lessons learned and I can't understand why new posters do not take advantage of this! All I can say is "Geez Louise". Accept that this problem cannot be solved except by a major redesign - which Lexus is not going to do - and move on! Unless you want a major headache from beating it against the wall, that is!

    PS - I guess I keep posting on the thread because I am addicted to it or a glutton for punishment or something!! No matter how much I vow to keep away from the thread out of frustration, I keep coming back. :-)
  • wwestwwest Posts: 10,706
    The service manager at Lexus of Bellevue told me that the really simply way to disable VSC temporarily was to create an engine fault.

    So I disconnected the MAF/IAT sensor connector on my 2001 AWD RX300 while the engine was running. The engine died almost immediately and wouldn't restart. When I reconnected the MAF/IAT it started right back up but with an engine & VSC failure indication.

    After about 4 drive cycles the indications went out.

    So for any of you that are experiencing the extended delay/hesitation symptom if you want to try and see if VSC is somehow related.....
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