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From my point of view, the jury is certainly still out on all this electronic control crappola being put into all cars these days. It will get worse before it gets better and is certainly something we all will have to live with.
point where the trans stops learning and doesn't learn any
more,than maybe we need to get trainers for these transmissions,have someone whose trans is perfect train
your car for you.I wonder if we had all the posters with
problem transmissions switch there cars with the non-problem ones and let those drivers train their cars what
would actually occur.
Application of pressure to the acceleration pedal while in park or neutral would in most cases be an anomaly, Ooops, bumped the pedal and only sustained application "should" be responded too.
And no, I never heard that Nova story/rumor but there is the one about a clone of Ken Olsen's 16-bit off-spring rescuing the pioneer 10 program as the probe exited the solar system.
If you follow wwest's posts on this and other boards, you will see that the hesitation does not appear to be a transmission learning issue. Wwest has looked into this and found that the learning resets itself everytime you start the car and makes judgements on your driving style within the first few minutes of driving. I am completely non-technically trained so I am sure wwest can explain this better. but if this weren't the case, how could you ever have multiple drivers on one car, especially rental cars?
one avalon fron another,assuming no mechanical problem,it
would be interesting to get a driver who has a so called
perfect av trans(even if it's in his mind)to drive a problem one and see if he has any luck with the trans.
This difference may be among drivers; not cars. Numerous Avalon drivers who had "hesitation" problems were able to improve their car's response by changing the position of the foot on the gas pedal.
Changing their foot position seems to have worked also for readers who drive other car brand with similar problems. See
#11794 How do YOU step on the gas pedal? Initial Poll Results
and many following posts.
havalongavalon
If you prefer to let the car gain speed down a hill, and don't like this automatic downshift feature, you can usually override it by shifting manually into "S" and nudge it into 5th gear. If traveling at a slow speed, nudge it into the next gear up from the gear that is engaged.
havalongavalon
Is this happening to you while in "D"? Have you tried shifting to "S" and 5? This seems to help reduce indecisive shifting.
havalong
http://www.automobilemag.com/am/2006/toyota/avalon/safety.html\
The safest Vehicle out there for side impact.
Bob
These are my suggestions.
1. Never drive in "stop and go" traffic in the "auto" mode--I always use "2". The reason is that your transmission will re-program itself, interpreting crawling motion as a "driving habit", which no one has. In my case this effect is worse, since I am, admittedly, an extremely agressive driver.
2. Learn when the transmission shifts automatically, and avoid accelerating in city traffic if it about to downshift. This is what causes that "herky-jerky" feel. Try to always wait for shifts BEFORE pressing the accelerator. For example, if you are slowing down/braking, and then need to suddenly accelerate, if the car is about to downshift, and you press the gas, it will jerk forward.
3. NEVER, EVER put anything less than 91 octane in this car. 93 is better, and preferred, and will improve driving experience NOTICEABLY. For you money misers who are too cheap to by premium gas, I honestly suggest selling the car, and buying something else. This makes a MAJOR difference. I was forced to buy cheap gas one day, and felt as if I had changed my car, as it was jerking all over the place, and completely unable to shift smoothly. NEVER 87 OCTANE. NEVER, EVER.
4. If your driving style is very passive, the "herky-jerky" effect is worse. The tranny shifts very early, and often too soon. Consider accelerating fast every once in a while, to keep shifts more delayed. Remember, this car is smarter than you are, and knows what you do, a WILL second guess your driving.
5. In time this does get easier. I was frustrated when I first got my car, but now, after about 8K, I don't even notice shifting.
All of this might sound like too much trouble, however, I have never, ever bought a car that I didn't have to "learn" to drive--BMW, Mercedes, VW, etc. Remember, these are machines that are not perfect. Get to know your car, be patient, and, it will get better.
Last of all, on another subject. I THREW OUT MY CRAPPY MICHELIN TIRES LAST WEEKEND, and put on Yokohama Advan S4's, 225/55/17. I FEEL LIKE I HAVE A NEW CAR. Traction is dramatically better, I can corner faster, and the car drivers more like a BMW or Mercedes. I had them up to 115 mph last week on the highway (for only about 10 seconds), and the car felt as stable as if it were at 50 mph. Toyota is cheating us with such crappy tires on such a great car.
We all wanted a fix, right...?
Well...
Now it appears that the engine/transaxle ECU firmware has been modified to allow the engine torque, revs', to rise even if the transaxle clutches have not fully and/or firmly seated.
Toyota/Lexus was telling us that the engine/transaxle delay was in place to "protect the drive train" (allow additional time for the transaxle's clutches to fully and firmly seat during times of "unexpected" downshifts).
Now they have shortened the delay.....
Insofar as the need higher octane being somehow related, a cure, for these transaxle delay and/or over-rev problems I wonder if the DFI engines are being introduced to solve that issue once and for all.
All I can see as a result of using higher octane fuel is less need for downshifting, or "deeper" downshifting, when the car is caught, inadvertently, in a higher gear than appropriate for the current, "new" circumstance.
Bob
I advise each person that has this problem to complain by using NHTSA @ NHTSA.GOV and in the meantime continue to leave your car with the dealer time and time again. Georgia has a lemon law that can be imposed after three (3) complaints with no fixes.
Good Luck,
Cj
This proposal involved ASL, Aggressive Shift Logic, upshifting the transaxle whenever feasibly possible. Getting into a higher gear ratio "more" quickly will always result in lower average engine RPM and thereby improved FE.
Torque converter must be "lossy" by design, to supplant the need for a clutch the torque converter MUST NOT couple very much energy to the driveline at low engine RPM levels. So using the torque converter lockup clutch more often, to eliminate those losses, will also result in improved FE.
So, as of about the year 2000 Toyota began adopting these techniques.
That resulted, at times, in the gearbox NOT being in the most appropriate gear ratio for what the driver's next intentions might be, became.
As you come slowly to a stop the gearbox upshifts (feels as if being bumped slightly from behind) and then doesn't downshift into 1st gear until you have come to a full and complete stop.
And if you change your mind, now that the gearbox is in 3rd, before coming to a full and complete stop?
For the RX series prior to 2004 the gearbox would react always quickly and downshift simultaneously with the rise in engine RPM. These had a solid connection between the gas pedal and throttle valve.
As we all already know the earliest inceptions of this ASL technique, the 1999 RX300 for instance, is resulting in premature transaxle failures. Pretty rough on transaxle clutch frictional surfaces to have the vehicle be almost stopped and have the engine output torque level start rising rapidly while in 3rd gear and have to downshift into first quickly.
Burn baby, BURN!!
Sorta explains why ATF needs to be flushed every 15,000 miles, doesn't it..?
So, the 2004 and after RX330s (and others...??) get a DBW system to "protect the drive train", prevent the engine torque level from rising until those clutches can be fully and firmly seated.
Lots, loads of customer complaints result and not just a few written complaints to NHTSA.
What to do, WHAT to do.
Well, lets just change the firmware back so the engine RPM rises to the level desired by the driver as quickly as the driver can apply pressure to the gas pedal.
So now here we are at 2006 with 2007 models either here or on the horizon and the new engine/transaxle firmware has been adapted to eliminate the engine hesitation/delay effects.
In other words...
BURN baby, BURN.
With transaxle space so very limited in FWD vehicles just how small must those clutches be made in order to have 5-speed or even 6-speed transaxles?
Maybe Toyota has looked in to NASA's dust bin and found a clutch frictional material that will last for over 100,000 miles with the engine going "overspeed" during gearbox downshifts.
Or...
The engine hesitation/delay was deemed too hazardous to humans to warrant using it to preserve those clutch surfaces. Better to continue replacing transaxles than incur the publicity of producing cars that are clearly hazardous to the driving public.
Maybe Toyota has looked in to NASA's dust bin and found a clutch frictional material that will last for over 100,000 miles with the engine going "overspeed" during gearbox downshifts.
Or...
The engine hesitation/delay was deemed too hazardous to humans to warrant using it to preserve those clutch surfaces. Better to continue replacing transaxles than incur the publicity of producing cars that are clearly hazardous to the driving public.
Maybe comic relief was intended as a break from routine speculation?
That said, if it was a serious statement, how/why/where/to what extent would it qualify as "seriously hazardous to the driving public"? What an alarming condemnation, especially with no evidentiary substance anywhere on record!!!
with the trans if we buy a AV.
Here are some observations on above posts.
Premium gas burns slower than reg.,The es300,es330,and their camry counterparts have different epa ratings with
identical drive trains,my question is what is different in
these cars?,the gearing,the engine tuning,the fuel recomendations?
Do these cars come with synthetic atf?If not has anyone
tried amsoil or some other synthetic in the trans?
This would be worth a try for the posters having the most
problems.
I have used syn.for years in different atf's and found the
shifting to be quicker.
For those debating whether to buy a 06 or 07 AV the 6 speed
has 20%(trans) fewer parts,that would be a factor to consider.
As I mentioned in my post, my comments are apart from your obvious problem of over-reving. I have never experienced anything of the sort, and, if I did, I'd be quite upset, as I'm sure you are.
That being said:
1. If you have the same tires I did (Michelen MXV?) you are being cheated. Those tires are poorly rated all over the Internet, and do not do this car justice. I consider myself to be a driving enthusiast, and don't care how long my tires last. I have never driven one set more than 25K, and always "toss" stock tires when I buy a new car, with the exception of a BMW and Mercedes, which came with excellent tires. With my old tires, I experienced the "anti-lock experience" from time to time, yet, never once with the Yokos--my braking has improved, cornering dramatically more stable, and body roll reduced by about 30%--estimate based upon speed I can take known curves without roll, as opposed to before. They tell me I will get 30K aggressive miles out of them, which is fine for me.
I can't imagine how your car is driving using 89 octane. Trust me, if you put 93, your gas mileage will improve (I can get 36 mpg on the highway) and you will think you have changed your transmission.
I was told when I bought my car not to put anything but premium, and this is the word I've read in many other places. Strangely enough, however, neither the manual, nor the car, indicate this. I would dare say your problem COULD BE your gas. This car is so sensitive to this, that I can tell the difference between 91 and 93. When I used 87, my car would hesitate, and then LURCH FORWARD. No more with 93.
Regards.
If owners are experiencing better drivability by placing more of their foot on the pedal, that would explain a bunch and fits that theory well.
Remember - many owners don't experience these symptoms. Why / how could that be?
I'd be all over a service manager to attempt a fix by replacing my accelerator pedal and/or throttle body assemblies if I had a bad ride.
Absolutely correct kbondar. For some reason not completely clear to me, there are people who wish to portray the issue in a way to suggest that it is a huge safety issue and design flaw that affects all vehicles with that drivetrain, which is absolutely untrue. My car and three others I know of personally drive just great. In addition, it appears that there are well over two million cars produced with that drivetrain, yet the total complaints that can be found anywhere total less than 1/10 of 1% of all those cars.
Clearly hazardous? Mines not. And interestingly, the person making these claims neither owns one of these cars, or has even driven one that has the issue.
your position on safety is yours.
factually, just like me, you two don't own a vehicle with hesitation (how wonderful for us) and so your assessment of someone else's safety is based on what, lack of published numerical accident / incident information, or the number of forum entries you've read on edmunds and non-edmunds sites?
If someone experiences some degree of hesitation (i think we can agree from anecdotal information that for some it is non-existant, and for some- it is on the order of a 1/2 second to a second, perhaps more) and communicates they felt their safety was/is compromised in certain driving situations, who is anyone to refute that while being genuine?
To paraphrase you: for some reason, not completely clear to me, there are people who wish to portray the issue in a way to suggest that it is no safety concern.
WWEST nor anyone else is trying to take down the house of Toyota.
If anyone were to read his posts in the totality of the threads he is active in, they would not question his motivation.
So far, so good. If you're serious in your beliefs, I think some solid empirical evidence might settle the contention, but there isn't any. Sad, but true. Everyone will just have to settle for opinion.
That said, I have to say that any suggestion re someone trying to take Toyota's house down by expressing their opinion never entered my mind. Surely you jest!! Come to think of it, that's a really wild idea!! Why on earth would anyone think that, let alone grouse about it??
Bob
What I was questioning was the assertion that the hesitation they experience is "by design" and present in all two million other cars with that exact drivetrain. I base that on my own personal experience driving one for the last year and a half, plus the experience of two coworkers and a neighbor. All of our cars drive just fine. The design, as experienced in our cars, results in smooth quick acceleration. That by no means implies that someone else might not have a problem. But the assertion, as stated above, just does not fly. I do believe however that the NHTSA investigates, and takes action on any true safety issues they become aware of.
I think we can all safely assume that these transaxles "want", or programmed, to upshift and/or use the lockup clutch as much as possible in order to extend FE and maybe for other reasons. Let's also assume that the firmware design is such that the transaxle is EXTREMELY reluctant to downshift.
How does one go about programming a system that detects certain driver charactoristics and then applies them to the transaxle shift pattern??
Let's take a truly decisive driver for instance.
What would/might that driver do as s/he travels along the acceleration lane wanting for an opening in the upcoming traffic to merge into?
Would a decisive driver get completely off the gas for slight coasting, maybe even apply light braking, and then as a space is "approaching" make a very definite decision by quickly depressing the gas pedal...
On the other hand what might be the actions of an indecisive, not so sure of one's self, driver?
Fully release the gas pedal for slight coasting or dither it on and off? Apply the brakes lightly or heavily??
With a space approaching make an assertive depression of the gas pedal and then hold that position...?
Suppose these transaxles do not so quickly upshift if the ECU has "learned" that this driver is aggressive and almost NEVER comes to a full stop, a California STOP, at a stop sign. Maybe they even "know" to more quickly downshift if the driver has certain traits.
Bottom line is that until we know why these transaxles act this way, seemingly only with certain drivers or specific vehicles, how can we say the problem is NOT in ALL vehicles in the fleet?
I do expect a "smart" smooth shifting automatic.
Bob
Bob
Certainly if Toyota is actually using the DBW to "protect the drive train" then there would be no excuse for the firmware commanding the engine to develop torque, over-speed, until the downshift completes.
But more recently I have begun to see complaints of engine over-speeding during those same "traditional" AURD downshift incidents.
Am I wrong...?
If I'm right I suspect what we're seeing is a "refinement", evolution, of the engine/transaxle firmware.
Maybe Toyota is in the process of refining the firmware where it will be better at predicting which, or when, the driver will wish to soon accelerate rather than cruising along at the current speed or in the other case NOT coming
to a full and complete stop.
I wish them GOOD LUCK...!!
Bob
These recent messages seem to describe the same old, same old, occasional RPM surge that has characterized the Avalon since the early 2005 model came out, discussed many times in this forum.
Firmware doesn't seem to have been modified yet or if it was modified, it was apparently not improved.
As you and others have pointed out many times, a complex control strategy and some driver input assumptions are needed to achieve the Avalon's fast acceleration AND high gas mileage. A quirk of this control strategy is an occasional "racehorse" behaviour when stepping on the gas again after having slowed down to a ner stop or down a hill. This gas pedal input has to be VERY GENTLE.
Hi buzz123 and bobwiley,
A higher foot placement on the gas pedal seems to help, because it naturally tempers the magnitude of the foot input. The gas pedal is much more sensitive when depressed in its lower half.
The other thing that seems to temper misbehaviours is to routinely shift to "S" and 5, instead of "D".
havalongavalon
havalongavalon
Havalongavalon: As mentioned above, I've tried using "S" and it helps somewhat. It works on the hills, but not on the speed bumps. However, I have not tried the foot placement. Thanks for the suggestions!
Buzz
Putting your foot pressure higher up on the accelerator would undoubtedly require more foot pressure for a given pedal/throttle position. If a given driver tends to "dither" the accelerator pedal then that effect would be substantially reduced as your foot moves farther up the pedal.
That would indicate to me that the indecisive, somewhat hesitant, driver would be the one most likely to experience this problem.
Bob
I think that this situation may be compounded in the 2005+ Avalon because, in my view, the BRAKE pedal requires fairly HIGH pressure, whereas the GAS pedal requires very LIGHT pressure for average driving conditions, compared to my previous cars.
This means that in stop & go driving, when you frequently switch your right foot from gas to brake to gas again, you need to continuously re-calibrate your foot pressure depending on which pedal you step on.
Clearly, most drivers are able to naturally and automatically adjust their foot pressure depending on whether they step on the gas or the brake pedal. But for some drivers, this may be a more serious challenge. Conceivably, an indecisive or inattentive driver could at some time come off the brakes and step on the gas way too hard, and this would cause an unintended surge in RPM. Stepping higher on the gas pedal helps reduce this excess pressure.
One suggestion for improvement for 2007 (probably too late for the first 2007's since they may be already in production; but could be implemented at any time): re-design the gas and brake pedals so that their pressure requirements are more closely matched (make the brake pedal somewhat softer and the gas pedal a little stiffer).
havalongavalon
You chose a good example. Do you need to use the same strength to open your fridge door and microwave oven door? Or to close them? Probably not. And, probably you have unconsciously adjusted to these differences, and you apply the right amount of force to each. But sometimes you may forget, and yank the microwave door, or slam it shut -- ever happened?
Yes, we have to learn how much pressure to apply on any car's pedals. These properties can vary quite a bit.
Just like the pull that you clearly can feel from fish of different sizes will vary! (Yes, I thought that this would hit home!)
havalongavalon
i'd like to know if a problem car has a non-linear pedal position sensor (dead-spot), or if it has enough mechanical play on the low end that a position change isn't sensed by the sensor.