Lex4Bob

I had the "flash" done on my 2003 about three weeks ago and it was no good. The car acts the same. I'll be slowing down to 5-10 mph then thraffic light turns green before I come to a complete stop so I hit the gas and if feels like it's in neutral for a split second and then hits 1st gear abruptly. Almost as if the trans connot respond quickly enough and times out for a split second or so...

willard

If you browse about you will find owner complaints of throttle lag or engine delay/hesitation for Ford, VW, Toyota, Lexus and others, all concerning vehicles with automatic transmissions and mostly FWD or front biased AWD vehicles.

It is my firm belief that sometime in the mid to late ninties someone, or some group, with TONS of clout over the automtive industry issued an edict that the safety of FWD and front torque biased AWD had to be brought into line with their RWD and rear torque biased AWD brotheren.

My vote goes to the automotive insurance industry. Accident statistics most readily available, certainly with the CLOUT and enough synergy (read: "joint financial interests)" with the industry to want to keep this on the QT.

The safety issue involved the potential for loss of directional control due to engine braking, especially FRONT engine braking, in wintertime adverse roadbed conditions. There is also the issue of the potential for engine braking to interfere with ABS, again especially detrimental for FWD vehicles.

So, late in the last century the shift pattern/schedule was revised across the industry to address the safety issue. The new shift pattern dictated that anytime there was a FULL lift-throttle action by the driver the transaxle would be quickly upshifted so as to prevent any significant level of engine braking.

The problem that quickly arose from this change was that if the driver quickly returned to acceleration "mode" the engine was now at idle and the just previously commended upshift would deplete the ATF pressure/flow reserve. With little or no ATF pressure/flow available the subsequent downshift due to the driver's re-application of pressure to the gas pedal could not be quickly completed.

As evidence of this Lexus has now replaced a LOT of early RX300 transaxles.

By 2001 Lexus had figured out the problem and increased the displacement of the ATF oil pump, gear type oil pump, to provide more pressure/flow at engine idle.

So, the 2001 RX300's, even with all equipped with the extra ATF cooling via the tow package, OVERHEATS the ATF to the point that the recommended transaxle ATF service interval has declined from infinity (the life of the vehicle actually) to every 15,000 miles.

What to do, what to do...??

Oh, I know, let's use DBW, e-throttle, to delay the onset of engine torque until the subsequent downshift can be completed, the clutches firmly seated.

So the RX330 used the old standard ATF gear pump displacement but was equipped with DBW "to protect the drive train".

Regretably some one else in engineering had already decided that the VC, Viscous Clutch, in the AWD version was contributing to the overheating of the ATF and so it was removed, not to return until the advent of the RX350.

Is Lexus listening, do you suppose?

The final FIX...

SNOW mode...Assuming the new shift pattern upshift technique is to help alleviate accidents due to loss of directional control arising for engine braking, why not just have a SNOW mode that can be activated by the driver, by a rain sensor, or if the OAT hovers around or below freezing?

Upon a full lift-throttle event in SNOW mode the transaxle would remain in the same gear ratio (ready to SURGE forward on command) but the engine RPM, via DBW, would not be allowed to fall enough to provide a significant level of engine braking to the driven wheels, FRONT, rear, or ALL.

Absent being in SNOW mode the shift pattern could be the same as it was pre-2000, NO upshifting on full lift-throttle events.

No HIGH potential for engine braking, FRONT especially, to put your life at risk or interfere with ABS if the roadbed traction is satisfactory.

I guess on second thought ABS interference via engine braking might still be an issue. But that could addressed by keeping the upshift pattern but delaying it until the brakes are applied.

mbud

Okay, since i purchased my 2002 es300 with 98,000kms ive been experiancing this exact problem with my transmission. The constant lagging and hesitation when changing gears, especially around the 15-30km/h range. Driving in traffic is terrible, i feel like a bobble-head when i drive my car. Im beginning to get sick of this... i didn't buy a KIA, i bought a Lexus, this is not the type of ride quality i was expecting.

I live in Toronto, Canada... does anyone have any recomendations on what i should do to solve my problem?... Is it better to contact Lexus Canada? or a Lexus Dealer...? Or should i approach legal action...?

steviej

iTrader: (1)

are you still on original ECU programming or have you reflashed with the most recent version?

steviej

mbud

As far as i know...i'm still on original ECU programming. I purchased the car used, so how do i find out if its been reflashed or not?

Also, if it hasnt... what do you recommend?

amf1932

Since a Lexus dealer has to do this ECU flash, they'll check in their database to see if that flash has ever been done on your car.
As far as doing it, I won't comment on this point since it's debatable as to whether it's an improvement. Some people like it, and others don't.
Just be aware that once this flash is done, it's irreversible!

mbud

Well wont a flash cost me money? or is it covered by Lexus, since it's their mistake...? (I'm currently at 123,000kms and it's a 2002)

I'm worried that if i have to pay for the flash and it's not really effective (as i've heard from other people's comments, then whats the point in bothering with it in the first place...

steviej

iTrader: (1)

i actually like the reflash better than the original programming. The benefits far outweigh the few drawbacks in the latest verison.

One way to find out about the cost.....call and ask. Appeal to the fact that they may gain a new customer if they do not charge you for the reflash. Since it was a TSB released by Lexus, and you are the new owner, not an owner that has been hemming and hawing about it, they may waive the cost.
You won't know unless you ask. They should act in good service if they want to gain a future customer.

steviej

mbud

Okay so i went to the local Lexus dealership in my area and talked to them about my transmission lag... I gave them my VIN and they checked my history because i wasn't too sure about it. Turns out my computer has been flashed in 2004, but it doesnt say that anything has been done since.

As a result the service/parts guy told me what they can do is hook up my car and perform a diagnostic on it to see if the computer had any updates done to it since 2004. A diagnostic would cost me $55, and if it turns out that there is a new flash avaliable for my car since the last one performed then it will only cost me an additional $15 to do that. In the case that there isnt anything new avaliable, what they can do is erase my transmission's memory so that it wont have habits from the previous owner (service guy said this MIGHT help), and this would be absolutely free.

What does you guys think about this? Any recommendations?

steviej

iTrader: (1)

they are not steering you wrong. There was the first attempt at a reflash program that came out in late 2003. Many people did not like it. In April 2005, a second programming became available. It has the same TSB number, except with an R at the end. R stands for revised. That is the one the most of the discussion in this thread is about and the pdf file attached somewhere in this thread depicts.

For $70, that is not a bad price since you can't get the reflash anywhere else.

As for erasing the tranny memory, you can do this yourself by disconnecting the negative cable to your battery for a minute or so. Disconnecting and reconnect the battery will the ECU to default programming and it will learn your driving habits all over again. I actually do this every once in a while when I am bored.

steviej

mbud

haha Ok, Thats good news then!

I'll book an appointment with them as soon as i find some time! (Note: Sorry i mis-understood, the price in total with a flash is $85. Still fairly cheap in my opinion...)

As a reference could someone provide me with the TSB number for the flash that was introduced in April 05'?

amf1932

The most recent reflash is TC003-04R.

kpxus

I bought 2002 ES300 Certified last month having trasmission lag. After reading all kind of comments, i went to the the service dept guy to ask about his feed back because I dont want to get into another trouble by updating the flash. I asked him about his opinion, he told me it is better to live with current lag. Now , i am confused because of steviej comments.

Can any one tell me , in what aspect the tranny is behaving better once you reset? will it take 2000 miles drive to study your driving style ( i heard it from service dept)?

thanks

steviej

iTrader: (1)

Here is what is removed by the latest revision TC004-03R (please note, these are based on my observations and other members may have other experiences):

1. The long delay and ultra high revs of the engine that occured when you stomped on the gas pedal. Say you motoring along at 25-35 mph and go to pass someone, you stomp the pedal, the engine races to 6k rpm but you go nowhere, the tranny doesn't downshift, nothing. A second or two later, the tranny wakes up and downshifts one gear too many and off you go. This problem is gone.

2. The constant gear hunting at 40-45 mph. The tranny wants to go into 5th gear but the speed does not seem fast enough, so you get this faint shutter or joggle. Speed up and the joggle goes away, slow down and the tranny drops to 4th and the joggle goes away.

Here is what results from the latest revision.
1. The tranny takes a little longer (milliseconds) to kick down to lower gear than people are comfortable with. You slow down rapidly to almost a stop and then hit the gas to rapidly speed up, the car bucks more than most people are comfortable with.

2. The tranny does not seem to stay in 2nd gear very long. On very rapid acceleration it seems as if it almost goes from 1st to second. It doesn't but the time spent in second is quick.

I was able to adapt to both verisons and personally am more comfortable with the latest revision than the original programming.

mbud, here is the pdf file that has the 4/05 revison. click and print it.


steviej

amf1932

I had the last re-flash done on my '03ES300 done on May 24, 2005, so was that the TC004-03R, and if so, when was the TC003-04R issued?
The reason I ask is because I checked back on a post of yours from April 2005and I copied and pasted exactly what you wrote, "The most recent reflash is TC003-04R."