02-06 Transmission hesitation problems

[jragosta]

I called my dealer to schedule the 30,000 mile service. Since I've given up on the transmission, I didn't mention it, but he said that there's still another upgrade even newer than the one I had done a couple months ago. He told me that they're still trying to get it right.

Once I get the newer one done, I'll post the results. However, after the last one, it was OK for a few weeks and went downhill from there, so it will take a while before I know.

Bottom line is to keep pestering your dealer since Lexus keeps tweaking it.

[amf1932]

I called my dealer to schedule the 30,000 mile service. Since I've given up on the transmission, I didn't mention it, but he said that there's still another upgrade even newer than the one I had done a couple months ago. He told me that they're still trying to get it right.

Once I get the newer one done, I'll post the results. However, after the last one, it was OK for a few weeks and went downhill from there, so it will take a while before I know.

Bottom line is to keep pestering your dealer since Lexus keeps tweaking it.

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If possible, could you ask your dealer if he has a TSB number for this update? This way I could speak to my dealer and ask them if they have it available.

[Lexusfreak]

Good lord,

how many 'upgrades' can they possibly do?

[jragosta]

Good lord,

how many 'upgrades' can they possibly do?   

 

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As many as it takes?

At the rate they're going, it looks to me like they don't have any clue and they're just trying things randomly hoping that they'll eventually get something that fixes the problem.

[blake918]

Just for the record, I was behind a gentleman today picking his 04 LS430 up after having the tranny reflash to help his hesitation problem when I dropped my ES off for service today.

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I've driven a couple LS430s (both 2005s), and the transmission lag was terribly noticeable. It felt like the car was stumbling in between the gears. I don't accelerate hard either. One of the LS430s I drove was brand new (the other is a relatives that has 5k miles), and I drove it back to back with the competition from BMW (745li) and MB (S430), and I couldn't feel any lag. It was really disappointing to expereince such behavior from a LS430.

[jragosta]

I called my dealer to schedule the 30,000 mile service. Since I've given up on the transmission, I didn't mention it, but he said that there's still another upgrade even newer than the one I had done a couple months ago. He told me that they're still trying to get it right.

Once I get the newer one done, I'll post the results. However, after the last one, it was OK for a few weeks and went downhill from there, so it will take a while before I know.

Bottom line is to keep pestering your dealer since Lexus keeps tweaking it.

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If possible, could you ask your dealer if he has a TSB number for this update? This way I could speak to my dealer and ask them if they have it available.

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I just got back from the dealer. The service representative I talked to is mistaken - the June update is the latest. They did reset the computer again, but I can't imagine that the end result is going to be any different than before.

[05ES330]

Apologies if this had been addressed earlier. But I just had my 05 ES in for service. As usual I complained about the transmission which in my case meant the car occasionally seemed confused which gear to use and when coasting through a stop sign, no amount of throttle input would result in a smooth transition. The service manager said their had been two updates since my last complaint in April. The car is much improved, the stop sign thing isn’t perfect but about 90% better. Overall I’m very happy with the change and would recommend it to others.

[jragosta]

Apologies if this had been addressed earlier. But I just had my 05 ES in for service. As usual I complained about the transmission which in my case meant the car occasionally seemed confused which gear to use and when coasting through a stop sign, no amount of throttle input would result in a smooth transition. The service manager said their had been two updates since my last complaint in April. The car is much improved, the stop sign thing isn’t perfect but about 90% better. Overall I’m very happy with the change and would recommend it to others.

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I had the most recent one in June. It worked quite well for the first few hundred miles, then got progressively worse. After about 2,000 miles, it was terrible. Not the same hesitation at 40 mph when pulling onto a freeway, but a lot of very hard shifts at low speed.

They reflashed it in my last visit. Initially, it was great again, but then it started to stumble and shift hard. If they would reflash it again and somehow stop the transmission from learning all its bad habits again, it would be fine.

[aminklein]

:cries: I just bought a 2005 ES 330, and I'm very dissapointed with the performance. Unfortunately, I just discovered this Lexus forums and some others, and and am amazed to find all the complaints about the transmission. I have a car with only 700 mi, and the transmission performance is the worst of any car that I've owned. The constant hesitation and subsequent "jerking" forward, not to mention the rough shifting are driving me crazy. The advice from Lexus and my local dealer in Northborough, MA only suggest using a higher grade of gasoline. The local dealer claims there is nothing wrong with the transmission. The state Lemon Law requires me to get at least three attempts by a repair shop to correct the problem, but the dealer claims there is no problem. Frustrating

[amf1932]

Sorry to hear about your problem, but when I started this thread in 2003 I had the exact problems that you're having. I've had the transmission re-flashed twice to try to correct it, but all it did was change certain characteristics of the shifting, but never, was it what I considered, a good, smooth, transmission. As said by others, this could be caused by the electronic throttle......but I never believed it! You'll have to live with this idiosyncrasy or sell the car. :(

P.S. I've used both regular and premium fuel and it didn't make a difference in the crappy shifting.

[mikek753]

:cries: I just bought a 2005 ES 330, and I'm very dissapointed with the performance.  Unfortunately, I just discovered this Lexus forums and some others, and and am amazed to find all the complaints about the transmission.  I have a car with only 700 mi, and the transmission performance is the worst of any car that I've owned.  The constant hesitation and subsequent "jerking" forward, not to mention the rough shifting are driving me crazy.  The advice from Lexus and my local dealer in Northborough, MA only suggest using a higher grade of gasoline.  The local dealer claims there is nothing wrong with the transmission.  The state Lemon Law requires me to get at least three attempts by a repair shop to correct the problem, but the dealer claims there is no problem.  Frustrating

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that would be nice if you could return the car back by Lemon Law!!!

But, I think that that isn't a problem from Lexus point of view as it runs as designed

Also it's so much flustrating as almost every new ES owner discovers the problem after several weeks of use!!!

[amf1932]

Also it's so much flustrating as almost every new ES owner discovers the problem after several weeks of use!!!

It didn't take me several weeks! I noticed this problem immediately as I drove off the first time from my dealer.

[98es]

It didn't take me several weeks! I noticed this problem immediately as I drove off the first time from my dealer.   

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Is this not something you noticed during your test drive? I honestly knew what we were getting into when we got the '02 because it drove the same after we bought it as it did before we bought it. I had also done research on it but since this is not my primary car(mine's the '98) it didn't bother me as much and I didn't see it as dangerous. Sure, it stinks, but a part of me feels like we whine so much about it over and over again (me included). If you REALLY hate it, sell it. Believe it or not the 02-05's are bringing good money. Just my two cents, not trying to step on anybody's toes or anything.

[amf1932]

It didn't take me several weeks! I noticed this problem immediately as I drove off the first time from my dealer.   

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Is this not something you noticed during your test drive? I honestly knew what we were getting into when we got the '02 because it drove the same after we bought it as it did before we bought it. I had also done research on it but since this is not my primary car(mine's the '98) it didn't bother me as much and I didn't see it as dangerous. Sure, it stinks, but a part of me feels like we whine so much about it over and over again (me included). If you REALLY hate it, sell it. Believe it or not the 02-05's are bringing good money. Just my two cents, not trying to step on anybody's toes or anything.

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I was aware that they had this problem in the '02 ES's, but I was told by the salesman that it was corrected in the '03's. I never test drove the '03, figuring that the transmission was at least as good as my '94 ES that I traded in......my mistake.

This IS my primary car and I don't feel that the losses I'd incur with selling this car at this point negates my selling this '03 after such a short time. It doesn't make economic sense to lose over $10K after only 2½ years of ownership, and 14K mileage.

[SW03ES]

Lessons learned:

1. Don't listen to salespeople. They rarely know what they're talking about.

2. Don't buy a car until you drive it first.

[tdgreer]

I thought this problem was unique to my car until I started researching the problem yesterday. Wow. I can't believe this is as big a problem as it is and I certainly wish Lexus would take it seriously do something more than what appears to be temporary fixes.

I purchased my car in April of 04. It took a week or so but the problems with the hesitation became very apparant. At the 1000 mile checkup, I mentioned it and was told to give it some time since it's a new car. At the 5000 mile checkup I mentioned it again. They said they checked it out and it was "driving as designed". At 10,000 checkup I got really nasty about it and they still said they couldn't find a problem. At 15,000 (end of Sept 05) I brought it up again. This time they acknowledged a problem and did the re-flash, or fix mentioned here in this thread. It is better now, but still not what it should be.

This morning I took the car in because on Saturday morning I went to start it and it scared the heck out of me with a really loud noice... like extremely loud knocking. I turned it off quickly as it sounded like something tearing up under the hood. I wondered if an animal somehow got into my garage and into the car. Anyway, I started it again and had the same problem. After about 5-6 starts, it finally quit. It didn't go it again. But I took it in this morning and of course they found nothing. While there, I mentioned this hesitation thing again to the service guy and he put his pen down and had this total frustrated look on his face and said that yes, it's a big probem and they get a new fix for it about every 6 months... but nothing that really fixes it.

I filed a complaint with the NHTSA this morning. I really hope Lexus will step forward and do something. Their shining reputation is beginning to dull.

Oh, and also, what does this all mean as far as the value of the car? When I'm ready to trade in or sell?

[texagun]

I don't think Lexus will EVER address this problem as long as people are buying these cars, unless there is a HUGE Class-Action lawsuit against Lexus forcing them to fix it. Their profit margin is the bottom line and until it starts costing them money, they have no incentive to fix it. SAD!

[mikek753]

I don't think Lexus will EVER address this problem as long as people are buying these cars, unless there is a HUGE Class-Action lawsuit against Lexus forcing them to fix it. Their profit margin is the bottom line and until it starts costing them money, they have no incentive to fix it. SAD!

by Lexus definitions that isn't a problem

it works as designed

no problem -> nothing to fix

next time so many ppl will not go the same route ...

[wwest]

Proposal for an aftermarket device to fix hesitation problems in all Toyota/Lexus 5-speed transaxles.

Constantly monitor the gas pedal position via the OEM hall effect sensors. If/when the gas pedal returns to the "neutral' position check to see which gear the transaxle is currently in and automatically change the "shifter" electrical gear control contacts (there is no mechanical connection) to "command" a one-level downshift.

If the brakes are applied simultaneously with the gas pedal being returned to neutral then "command" a downshift all the way into first. The vehicle will not downshift until the appropriate lower speed is reached.

In both cases while the transaxle may not actually downshift due to roadspeed being too high it certainly would not upshift and later leave you waiting 2 to 3 seconds for it to downshift back into the most appropriate gear ratio for the acceleration level dictated by the new gas pedal position.

If these were RWD vehicles I wouldn't hesitate to bring such a product to market but with FWD we would be incurring the liability that arises from FIRM engine compression braking on the front wheels.

[monarch]

In recent weeks had the opportunity to rent:

A 2005 Toyota Highlander with the electronic throttle V6 & 5-speed automatic

A 2006 Toyota Camry with the electronic throttle 4 cylinder & 5 speed automatic

A 2004 Toyota Camry with the cable operated throttle 4 cylinder and 4 speed automatic.

The 2004 Camry with the cable operated throttle 4 cylinder provided the most instantaneous throttle response.

The 2006 Camry with the electronic throttle 4 cylinder had a very slight hesitation, but was not enough to be annoying. Overall the 2006 Camry was a joy to drive, providing an abundance of energetic power and perfect transmission response in all driving situations. I came away totally convinced Toyota knows how to make the electronic throttle and 5-speed automatic work exceedingly well.

I was not as happy with the electronic throttle V6 & 5-speed automatic in the Highlander. The hesistation was noticable and definately annoying at times. In any case, I havn't heard of hesistation complaints with the 2006 Avalon so I assume Toyota has already found a way to make the electronic throttle work with the latest V6's.

[wwest]

A True Story....

Several years ago TeamSeattle(.com) ran two Saleen SR-7s at the 24 Hours of Daytona. Prior to the race one of the cars had been over-heating and had to be torn down to replace both radiators.

Just before race time, really too close for comfort, the car was finally re-assembled and when the engine was started it immediately went WOT and luckily was shut down before anything was damaged.

For some reason the engine control ECU had "forgotten" the parameters for the DBW gas pedal/throttle control system.

Picture this....

A technician laying upside down, butt on the drivers seat, head and shoulders in the brake/clutch/gas pedal "tunnel". At the same time the Saleen factory engineer, white shirt and tie, is standing behind the cab with one foot on each exhaust manifold of the big-iron Ford V8, laptop computer laying on the cab top in front of him.

The Saleen engineer has the technician alternate the gas pedal position between "neutral" and WOT while he manually moves the throttle itself to the same, appropriate positions, meantime using the laptop to "tell" the Saleen's engine ECU to "trap" the sensor signals to save the positional parameters to coordinate the throttle valve position with the gas pedal.

Often wished I had made a video of the procedure.

So, how does your car "learn" these DBW parameters, for learn it must. And does it continuously re-adjust those parameters from time to time if it decides the previous parameters are for some reason no longer valid? Floor mat laying lightly on the gas pedal for instance.

Or someone left foot braking???

I can imagine a VERY confused engine/transaxle control ECU should the gas pedal suddenly go "negative" from the previously memorized neutral position established while that floor mat was in place and now removed or someone's right foot being finally removed from the gas pedal after "resting" there even with the brakes applied.

I have no doubt that the previous "false" neutral gas pedal sensor parameter would be immediately scrubbed, erased, but how long would it take, and HOW would it, go about re-establish a "certain", for sure, neutral position parameter?

And just how would the transaxle "act" until a new gas pedal neutral position parameter is memorized?

[wwest]

You will NOT believe this!

Googled for "Atkinson cycle" & "intake noise".

I was curious if the intake noise from the Atkinson cycle's reverse airflow, combustion chamber back into the intake manifold, in a 3.3L V6 might be at least part of the reason the RX400h doesn't make use of this fuel economy method.

Inadvertently found:

July, 8th, 1999 Final report by SRI, Sierra Research Inc, on "Alternative and Future Technologies for Reducing Greenhouse Gas Emissions from Road Vehicles"

One of the conclusions is that if the industry switched to 5-speed automatic transmissions, made use of ASL, Aggressive Shift Logic (quicker upshifts), early torque converter clutch lockup, and shift into neutral with brake application and engine at idle, a 9.8% improvement in fuel economy would result. Industry response was that "driveability" would suffer.

Welcome to 2006.

[wwest]

2004 RX330 electrical wiring diagram Pub. No. EWD563U page 177.

(Quote)

"4. Mutual System Control

To efficiently operate the VSC system at its optimal level, the VSC system and other control systems are mutually controlled while the VSC system is being operated.

Engine Throttle control.

The engine power does not interfere with the VSC brake control by controlling the opening of the throttle and reducing the engine output.

Engine control and electronically controlled transmission control.

The strong braking force does not interfere with the braking force control of the VSC system by turning off the accel. and reducing changes in the driving torque at shift-down."

(End quote)

As one can readily see from the above statements the inadvertent operation of the VSC system can result in engine dethrottling and delayed downshifts.

If the VSC detects over-stearing it will apply, modulate, the brakes on the outer turning wheels. The greater the degree of over-stearing the harder that outer front wheel will be braked.

On the detection of under-stearing it will apply both rear brakes (RX330 only??) while controlling engine power.

Notes:

"The engine power does not interfere with the VSC brake control by controlling the opening of the throttle and reducing the engine output."

Take notice that this statement does not necessarily mean that engine power is reduced to idle. It may mean that engine power is "set" to match road speed, no acceleration torque nor any compression braking.

"The strong braking force does not interfere with the braking force of the VSC system by turning off the accel...."

...turning off the accel....

I take it this means opening the firmware control loop between the gas pedal (accelerator) and the throttle valve.

Therefore I take this to mean, again, that the engine throttle control is taken over by VSC to prevent any significant level of engine compression braking.

"...and reducing changes in the driving torque at shift-down..."

Wouldn't this mean delaying down-shifts until the VSC ceases operation?

Since for most of the vehicles exhibiting the hesitation/delay the "outer turning wheel" is also one of the two driven wheels, or as a minimum for AWD one of the two primary drive wheels it is no surprise.

I think we already know that the VSC system firmware has a proactive mode wherein it dethrottles the engine to alleviate the potential for rollovers in an accelerating and/or tight turn.

So, what might make it, the VSC system, think it needs to "operate" just before coming to a full stop or just as you decide to downshift for acceleration.

An unequal rotation rate at the driven, front, wheels versus the rear, that's what!

Would those of you experiencing this problem please, if you don't mind, check and be sure all of your tires are equally inflated. Maybe even a pound or two extra in the front since the majority of the weight is there?

Remember that if you adjust the pressure you will need to "normalize" the new tire pressure levels.

[wwest]

A CLUE......

IMMHO most, or a clear majority, of the complaints of engine/transaxle downshift delay/hesitation in various forums all over the internet seem to involve only the FWD or front biased AWD versions of the Toyota and Lexus 5-speed vehicles.

The shop manuals tell us that if the VSC activates it assumes control of the throttle and the transaxle shifting sequence. The VSC only activates, really, if it detects over-stearing or understearing. When it detects under-stearing, "plowing", it applies the brakes to both rear wheels (at least for the RX300,330), on the assumption that slowing the vehicle even slightly might allow the front wheels to regain enough traction to alleviate the condition. For over-stearing it modulates the braking of the outer turning wheel according to the severity of the level of over-stearing.

As one can then see, the result of VSC activation and assumption of the throttle and transmission shift sequence might be entirely different for a FWD drive versus a RWD vehicle.

UNDER-STEARING:

When a RWD vehicle is understearing some level of engine compression braking at the rear, DRIVEN, wheels might even be desireable. Whereas on a FWD in an under-stearing situation engine compression braking on the wheels already having lost traction would be highly undesireable. Obviously allowing a downshift on a FWD vehicle during this situation might even lead to total loss of control.

OVER-STEARING:

To correct and help recover from over-stearing the brakes are applied to the front outside wheel. If the driver happens to be braking during the incident the VSC will actually release some level of braking at the inside front wheel.

The VSC activation will likely prevent all engine compression braking or even acceleration torque by modulating the throttle to match engine RPM to road speed. Obviously any impending downshifts would be delayed until the situation has passed.

So, for me, there is now enough information available to conclude that for whatever reason the VSC is activating, just ever so briefly, and causing these incidents of engine/transaxle shift delays.

Under-stearing, plowing, is much more common on a FWD vehicle, while over-stearing is more common on RWD vehicles, often the result of a too heavy throttle application.

So which driver is most likely to notice, let alone complain, about inadvertent and brief VSC activation and the resulting loss of throttle control and delayed downshifts?

And keep in mine that as you drive around that corner the front wheels are turning at a different rate than the rear and the outside wheels are turning faster that those on the inside of the turn. So if the VSC is somehow faulty (lack of sensor calibration or tire inflation disparity) and always on the "cusp" of activation accelerating around that turn would certainly trigger VSC.

[amf1932]

IMMHO most, or a clear majority, of the complaints of engine/transaxle downshift delay/hesitation in various forums all over the internet seem to involve only the FWD or front biased AWD versions of the Toyota and Lexus 5-speed vehicles.

I disagree. There are many complaints about this downshift hesitation on FWD also, so this negates the theory of under-steering or over-steering causing these problems. In fact, I was driving my brothers '05 LS430 recently and I could replicate the hesitation as I had on my '03 Es300.