Hesitation (jolt)

[lenore]

You guys are so lucky, at least lexus is stepping up to that problem, wish they would fix the RX300 AWD tranny problems. Too old, too late I guess.

[lewjeff]

Lexus has a fix for the hesitation.

I have an 05 RX330 and after a lot

of back-and-forth with Lexus and my

dealer, they applied the fix.

After a month of agressive driving,

the hesitation went away.

It still doesn't shift right, though.

Step on the brake while coasting

downhill and it downshifts....drives

me nuts as it happens every workday

as I drive home from work.

[panteragt4]

:) I have finally solved my 05 rx330 tranny hesitation,i got rid of it!I had the recalibration done and it slightly helped.I will not put up with a problem from a top notch company that they can't fix.This was my fourth lexus and it will be my last until i feel their products are up to the standards they claim to attain.I have gone to infinity and was extremely surprised and happy at how much better their performance was above lexus.I know their value for resale is not as strong as lexus but i feel a car that runs much better and has an equal too or better than build quality to lexus is itself more important to me than the money i'll get when i finally sell the car.I am not a lexus basher,far from it,i recommended lexus to many of my family and friends over the years and i still think its an excellent company but felt that i personally couldn't live with the hisitation problem.I hope that they find the problem so all of you can be a little more happier with the rx330.

thank you, jeff

[wwest]

Back in 1999 Sierra Research Inc, an industry consultant to CARB made three recommendations concerning automatic transmission control systems that would likely result in a 9.8% improvement in fuel economy and therby significantly reduced emissions overall.

1. ASL, Agressive Shift Logic. Assign high priority to upshifting the transmission into the next highest gear ratio as soon, as quickly, as possible given the current roadspeed but without incurring engine knock from lugging due to low engine RPM.

2. Shift the transmission into neutral at all times with the engine RPM at idle (not enough roadspeed to "drive" the engine above idle) and the brakes applied.

3. Early O/D clutch lockup. If/when feasible lock-up the O/D clutch in lower gear ratios other than O/D.

By 2001 Toyota had adopted all three of these measures.

The problem that quickly developed from that implementation was premature failures of transaxles, especially those that were under slight heavier duty than normal, Camry transaxle in an RX300...

So the 2004 and later models use a DBW throttle system to delay the onset of engine torque to "protect the drive train".

As you coastdown to a full and final stop for a traffic light or sign the transmission will automatically shift into neutral and into low gear as you come to a full stop. No problem.

But if in the middle of that coastdown, and after the system has shifted into neutral, you reapply pressure to the gas pedal the transmission must be quickly shifted into 1st gear. If you own an RX300 the engine torque will begin to climb before the "downshift" transaxle clutches can fully and firmly seat. If, on the other hand, you have an RX330 them the DBW system will be used to delay the onset of engine torque long enough for the clutches to seat.

Same goes for downshifting, sudden returns to acceleration, at highway speeds.

Note that the use of premium fuels are a modified IAT to artificially enrich the mixture would result in a lower engine lugging range, RPM, which would result in alleviation of some instances of downshifting (the engine still has "pull" at the higher gear already in use) and therefore fewer occurrances of hesitation or delay.

[Cheerdad]

Lewjeff

I have a 04 RX330 with 42000 miles that had the transmission hesitates; but have not said or asked my dealer to make any repairs to it. I had been happy reading this board for the last year waiting and hoping for a good and final repair. But, what I have noticed is every time I had the car in for service the transmission shifted differently when I would bring it home. Over the last year I feel the transmission has been flashed at least twice, and the two things I have noticed is. One the gas mileage has dropped about 2 or more miles per gallon on the road, and the transmission will down shift while going down a hill. I’m not real fond of either; but on the other hand I don’t feel I need to worry about getting hit when I pull out.

Cheerdad

[Rhody401]

Lewjeff

I have a 04 RX330 with 42000 miles that had the transmission hesitates; but have not said or asked my dealer to make any repairs to it. I had been happy reading this board for the last year waiting and hoping for a good and final repair. But, what I have noticed is every time I had the car in for service the transmission shifted differently when I would bring it home. Over the last year I feel the transmission has been flashed at least twice, and the two things I have noticed is. One the gas mileage has dropped about 2 or more miles per gallon on the road, and the transmission will down shift while going down a hill. I’m not real fond of either; but on the other hand I don’t feel I need to worry about getting hit when I pull out.

Cheerdad

I have an 04 also. I had mine flashed last summer, and it made an INCREDIBLE difference. The 2 second acceleration response delay (when trying to pull out into traffic - after coasting on an onramp) is gone. The strong jolt is also gone. The ride is much more comfortable. I highly recommend having it done. There have been no negative side effects here, and I feel safer now.

Mike

[COZ]

Got the ECM flashed last weekend. After driving it around on the city and the highway I can say things are much better. The response from a dead start is immediate, there are no more jolts and the highway mile seems a littler better. I can't see or feel any downside.

Additionally, it improved the flakey cruise control. I set it for 85 and it didn't downshift all the time while going up gentle hills.

[chimchim]

I'm really surprised people are saying they don't feel the jolt anymore. I got the reflash and it's smoother, but there's still a jolt.

[COZ]

Maybe its a driving style issue. I tend to drive with passengers and therefore I driver as smoothly as I can for thier comfort. That means smooth even application of the accelerator and brakes and smooth inputs to steering. Its not a sports car. Since the flash, I have not noticed the jolt. I'm still always evaluating it when I drive, looking for the jolt and I don't notice one and niether does my wife.

[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.

[COZ]

Isn't a buzzer supposed to sound when the VSC is activated?

I also added the VSC theory from Lexus.

CH_84_brake5.pdf

CH_80_VSC.pdf

[lewjeff]

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.

<CHOP>

I don't think that applies to the discussion, but I could be wrong.

The hesitation I experienced was straight-line driving (where I don't

think VSC comes into play).

In my case, the hesitation was when I was rolling at slower speeds

and punched it. There was nothing there for an unreasonable

delay.

[Rx330driver]

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.

<CHOP>

I don't think that applies to the discussion, but I could be wrong.

The hesitation I experienced was straight-line driving (where I don't

think VSC comes into play).

In my case, the hesitation was when I was rolling at slower speeds

and punched it. There was nothing there for an unreasonable

delay.

that was my thought too, and thats exactly when i get it as well. lol

[COZ]

Thats was my point as well. I don't think it's a VSC issue either. I think its more of a driving style issue.

Edit - Unless the flash didn't take? Maybe the dealer didn't flash the car correctly.

[wwest]

I'm not saying these are circumstances wherein VSC should activate, just theorizing that due to some design flaw and/or sensor miscalibration it is (partially, briefly??) activating.

Yes, there is supposed to be a buzzer sound and an indicator light if VSC activates. But again, what if it's activation is the result of some sort of firmware design flaw that is enabled by one of the two sensors being slightly out of calibration?

I can easily miscalibrate, and will, either of these sensors on my 2001 AWD RX300 but I don't expect to learn anything since my 2001 isn't DBW and therefore doesn't seem to be subject to the problem.

[Rx330driver]

I hate to bring back old threads, but i went to my service today, and brought up this ECU reflash. THis is what my service rep said. ITs non reversible, which i knew, and that many people said they dont like it after, and that the jolt actually gets worse in some cases. He also said that the shifts are much quicker, and yes it brings benefits, but he eventually convinced me to not get it yet until i get some good news from you guys. So, let me here it lol so i can bring it up at my next service.

[Rhody401]

I hate to bring back old threads, but i went to my service today, and brought up this ECU reflash. THis is what my service rep said. ITs non reversible, which i knew, and that many people said they dont like it after, and that the jolt actually gets worse in some cases. He also said that the shifts are much quicker, and yes it brings benefits, but he eventually convinced me to not get it yet until i get some good news from you guys. So, let me here it lol so i can bring it up at my next service.

Do it, the (May 2005) bug fix/correction makes a huge difference. There are no negative results that I have heard or experienced. It drives more like a Lexus now :)

You'll be very happy with the results.

[Booyah]

I hate to bring back old threads, but i went to my service today, and brought up this ECU reflash. THis is what my service rep said. ITs non reversible, which i knew, and that many people said they dont like it after, and that the jolt actually gets worse in some cases. He also said that the shifts are much quicker, and yes it brings benefits, but he eventually convinced me to not get it yet until i get some good news from you guys. So, let me here it lol so i can bring it up at my next service.

Trust me! GET IT DONE while your car is in there for brakes--reflash it! You will like it

[COZ]

Have you read the whole thread? Do it. Here is the TSB. Just give it to your dealer.

ECM_CALIBRATION_SHIFT_FEELING.pdf

[Rx330driver]

Have you read the whole thread? Do it. Here is the TSB. Just give it to your dealer.

YES! i brought this to him, all seven pages. And that is the reply i got, "make sure yo ureally want it cause people say it makes it worse" and some stuff about how the car will shift much faster. So i just wanted to get opinions from people who got it done.

[chimchim]

Have you read the whole thread? Do it. Here is the TSB. Just give it to your dealer.

YES! i brought this to him, all seven pages. And that is the reply i got, "make sure yo ureally want it cause people say it makes it worse" and some stuff about how the car will shift much faster. So i just wanted to get opinions from people who got it done.

I have yet to hear anyone on this board complain about the reflash. Everyone's responses ranges from "mild improvement" to "life is perfect now".

[Diana48]

I'm posting this for my wife, as she doesn't do this kind of thing. Her 2005 RX330 AWD has had the "hesitation" or whatever it is since we got it. The dealer just lies his head off about what causes it, what they have done to "fix" it and what they will do in the future. I have no confidence in them (Lexus of Dayton - OHIO) at all. Every time it is in the shop, they screw up something else. So far she has gotten a "free" $120.00 oil change, that had the car back in three times to fix what they screwed up. I have read this whole thread and copied the TSB referenced earlier and will take that into them, and ask if it was performed. The problems are secondary to the poor service.

[huylanalexus]

I'm sorry to bring you the old post. I know most everyone here already had the firmware upgrade. How is your car now?

I just got mine done a few days ago(38K). I noticed it's better now but I just start to worry the lag problem will come back like before. The car has been updated twice, 21K from previous owner.

Have anyone had a second update? Lexus only pay twice ECM calibration.

Thanks all.

[Running Ox]

I did ECM calibration last week. really better! I would like to recommend everybody to do it.

[TomC]

I did ECM calibration last week. really better! I would like to recommend everybody to do it.

What year is your RX? Oops, its a 2006. What did it cost?

Tom