Last post on Dec 06, 2013 at 1:02 PM
You are in the Toyota Avalon
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Toyota Avalon, Sedan
#10699 of 14965 Re: Transmission problem or not? [tedescm1]
Dec 17, 2005 (9:19 am)
About one year ago I drove my daughter's 2003 Lexus ES330 about 50 miles. It drove great,was quiet and handled the road conditions great, but the transmission hesitated 3 times, very noticeably on small inclines. My daughter did not notice the hesitations at all when she drove the car.
Before deciding on the Avalon I contacted a Lexus dealer and spoke to the sales manager about a new Lexus. I was told they would give me a great deal and wanted to see me. I asked about the hesitation in the transmission and all I got was "O" and thanked me for being interested in their cars and hung up.
Toyota has been aware of the comments and or complaints for a long time. There has been a lot of time to evaluate, confirm, redesign, and ultimalty fix it. I talked to three Toyota dealers and they all are aware of the transmission matter. What will it take to get it right? Is Toyota waiting for the majority of the Avalon owners to complain.
#10700 of 14965 Re: Transmission problem or not? [ange]
Dec 17, 2005 (10:49 am)
Given the vast majority of Avalon Owners don't seem to be complaining, perhaps the suggested "wait" will be a long one?
I question the idea that there may be a "problem" in a classic sense, at all. (NOTE: I'm not questioning those who say they've experienced hesitation --just that what they're experiencing may be more the way their transmission works,and it doesn't feel "right" to them) I also question the idea there's a "flaw" at the bottom of this phenomenon.
People point to the TSB and say it's evidence that a
"problem" or "flaw" exists. But is that a realistic statement? A TSB isn't a Recall. The entire product line isn't affected. Defective components aren't being replaced. The condition doesn't occur for everybody. It doesn't even occur the same way for everybody. Most TSB's are published to show service personnel how to modify components which are OK, but perhaps not fitted correctly and needs to be adjusted correctly. TSB's are in no way an indication that a "flaw" exists.
If there is a "flaw" in the design of these transmissions, CPU, or whatever, then why is not a universal occurrence? Why is that a quick fix by the dealer-- an "adjustment" to the CPU--eliminates the hesitation symptom for those who have it done?? That suggests the design of this system allows flexibility. Is this an indication of some kind of flaw? On the contrary, it suggests there's enough flexibility designed into the system to allow changes to be made--if and when needed. Obviously some feel they need it, and the majority don't seem to need it. A design with that kind of flexibility which allows adjustments to owner's individual needs isn't a bad thing!! Perhaps Toyota "got it right" right from the git go?
#10701 of 14965 Re: Transmission problem or not? [ange]
Dec 17, 2005 (11:10 am)
No, I suspect that Toyota and Lexus are waiting for the EPA, CARB, and the New York state's new CARB agencies to give them leeway to put hundreds of thousands, maybe even millions, of vehicles outside the Fuel economy and emissions specification under which they were originally shipped.
I have no doubt that the transaxle's firmware being all to willing to quickly upshift during throttle closed periods, however brief, resulted in some measurable level of additional fuel economy and lower overall emissions levels.
That's the way the transaxle in my 2001 AWD RX300 works, quickly upshifting, so this upshift firmware design began by 2001 at least.
But that resulted in an inordinate level of wear on the clutches being downshifted into due to the fact that the engine with a hard-wired throttle was already developing torque during the downshift response to follow-on gas pedal application.
So DBW was adopted to "protect the drive train", keep the engine from developing torque until the clutches could be fully and firmly engaged.
And at about the same time upgrading to a 5-speed transaxle which of course added significantly to the firmware's complexity. Now throw in the additional fuel economy requirement of the firmware to select the highest gear ratio possible based on roadspeed and "current" gas pedal (engine torque level "command") position.
And now just as the "proper" downshift is selected and commanded the driver eases the gas pedal farther down just slightly.
Now if left in the previously selected/commanded downshift the engine would most surely lug down and knock/ping so an additional downshift level is quickly selected but cannot be commanded until the previous downshift command has completed.
And just maybe the transaxle's hydraulic control pressure accumulator reserve is exhausted and pressure must be "rebuilt" with the engine still at idle.
All the while the DBW keeps the engine at idle to "protect the drive train".
And now the driver senses the hesitation and applies even greater gas pedal pressure......
#10702 of 14965 Re: Transmission problem or not? [hylyner]
Dec 17, 2005 (11:34 am)
"..then why is it not a universal occurance?.."
Overall component tolerances..!
We can all be quite certain, safely, that the engine design engineers are very good, even excellent, at their jobs.
But one of the higher, over-riding engine design goals these days is fuel economy and lowering emissions. So by 2004 (RX330) a "lean burn" technique was developed using a higher resolution knock/ping sensor to be certain that NO ENGINE would be subjected to damage due to running the A/F mixture at the new "target", 16:1(?), level.
Look at the fact that many new models now have both intake manifold fuel injectors and high pressure injectors for injecting fuel directly into the compression chamber at or near TDC.
All to provide a stratified charge, RICH A/F mixture surrounding the spark plug, but overall a leaner mixture than could otherwise be used.
That's EXTREME IMMHO!
So for just a few engines all of the tolerances add up on one side, the wrong side, and those engines end up being slightly more prone to knock/ping. No sweat, say the engineers, the new sensor will detect even the slightest level of knocking and the firmware can be designed PRIMARILY to not operate those engines in the parametric regions most subject to causing knocking..
In other words don't enrich the mixture to alleviate pinging (that will get us in DEEP trouble with the EPA, CARB, etc,), just don't lug the engine so far down on the torque curve that it pings.
But I remain convinced that the upshift that occurs in my 2001 RX300 at extremely low speeds, or just before coming to a full stop is there to prevent inadvertent loss of directional control with FWD in case the roadbed happens to be slippery.
#10703 of 14965 Re: Transmission problem or not? [wwest]
Dec 17, 2005 (1:10 pm)
I'll warrant the idea of "variations in component tolerances" is worthy of consideration. I've already supported the contention that fuel economy, emission control, and driveline optimization are the underlying reasons why DBW systems behave as they do .
I do not, however, agree that a "design flaw" is the root cause of what's being bantied about in this discussion. The fact that an "adjustment" or "reprogrammed CPU" can make the phenomenon go away (ergo, compensate for variations in component tolerances) tells me the design is a good one by virtue of its flexibility, and not "flawed" in any way. On the contrary, it may in fact be better than it is given credit for.
The only reason I can think of for those who advocate the "flawed" concept is that it becomes a convenient pretext for dissing the manufacturer.
#10704 of 14965 Re: Transmission problem or not? [hylyner]
Dec 17, 2005 (2:33 pm)
I happen to have some of the world's absolute best, brightest, programmers working for me, lucky I guess.
I don't think any one of them would content that a fix, TSB, requiring a "reflash" of the non-volatile memory would be the result of anything but a design flaw. When we make a mistake in our software or firmware designs we never hesitate to call it as it is, the previous release contained a design flaw.
I have been a champion of Lexus since my very first one, a new 1992 Lexus LS400, which is still running great at over 100,000 miles. But at the same time I have never been shy about "dissing" them for the design flaws that somehow get incorporated in the vehicle design.
It has been a long road since I started complaining about the design flaws in the automatic climate control in my 92 LS, and generally therefore in all Toyota and Lexus vehicles. Three of the proposals I made back in 1993 to correct these design flaws have now been adopted, two of those in 2001 and the latest in 2005. A few more and "Perfection" will have been fully pursued insofar as automatic climate control system design is concerned.
"..(ergo, compensate for variations in components tolerances)..."
The wide bandwidth high resolution knock sensor signal is the method used to detect, and provide for a method of compensation, for component tolerances.
The firmware's embedded "reluctance" to downshift into the MOST appropreate gear ratio for acceleration torque rather than the gear ratio for the best fuel economy is the design "flaw".
How many of us, driving a manual transmission vehicle, in any of the three known hesitation circumstances described in the TSB, would simply engage the clutch during these inadvertent coastdown periods? The only exception might be if we noticed a need to more rapidly accelerate than would be pertinent in the current gear ratio. In that case a downshift would be the most appropreate move.
So the transaxle doesn't have a clutch...but what harm would come from simply leaving the gear ratio as it is for a few moments during initial coastdown?
#10705 of 14965 Re: Transmission problem or not? [hylyner]
Dec 17, 2005 (2:53 pm)
Any system that corrupts itself and requires resetting or a cold reboot to resume normal operation cannot be deemed "a good one by virtue of it's flexibility".
A robust system is one that operates imperceptibly and with flexibility within normal operating conditions, without requiring the end-user or driver in this case, to significantly change normal behavior to compensate for it's limitations, and certainly one that does not require frequent hard resets or reflashes.
#10706 of 14965 Re: Transmission problem or not? [alan_s]
Dec 17, 2005 (3:35 pm)
No offense intended for either yourself or Wwest, but I'll stick to my belief: "The only reason I can think of for those who advocate the "flawed" concept is that it becomes a convenient pretext for dissing the manufacturer."
Should that be your reason for feeling as you do, all one can say is "to each his own". If it isn't, then you would have to agree that in spite of your feeling as you do, Toyota makes a pretty darn good automobile, flawed or not.
#10707 of 14965 2006 AVALON XM RADIO
Dec 17, 2005 (4:25 pm)
I ORDERED MY AVALON LIMITED WITH A"FACTORY INSTALLED" XM RADIO. WHAT I RECEIVED WAS THE XM BUILT INTO THE JBL SYSTEM, BUT INSTALLED BY SOUTHEAST TOYOTA IN JAX WITH A VERY CHEEZY ANTENNA. THE CAR IS PINE ANT THE ANTENNA IS ABOUT TWO INCHES SQUARE AND ONE INCH HIGH IN BLACK AND MOUNTED ON THE RIGHT EDGE OF THE TRUNK LID WITH THE WIRE RUNNING OVER THE EDGE OF THE TRUNK LID AND DOWN THE INTERIOR OF THE TRUNK HINGE. I WAS EXPECTING A ROOF MOUNT ANTENNA OR AT LEAST A COLOR COORDINATED CENTER TRUNK MOUNT.
CAN ANY ONE COMMENT?
#10708 of 14965 Re: 2006 AVALON XM RADIO [liners]
Dec 17, 2005 (4:37 pm)
VERY CHEEZY ANTENNA
You have options. Do a search on Terk XMicro antenna. It is small, and can be mounted inside the car. I have one mounted underneath the windshield - almost invisible - works fine. If you want to, you can get that CHEEZY antenna off your trunk.