I wonder if you and I are having the same issue. Here's been my experience: I dropped my car off on Thursday for the TSB at Lexus. TSB includes both ECU and TCU update. Supposedly the ECU update on my 500 went perfectly, but when the tech tried to update my TCU it fried it. The dealer then overnighted a brand new TCU which came yesterday (Friday) and the tech attempted the TCU update once again. Fried the TCU a second time. Now a case with Lexus of North America has been opened and they're also getting an engineer involved. As a result, I am also stuck with a loaner this weekend. I wonder if the issue is hardware, software, or user error...

 

Interesting. I'm not sure they have done anything to the car yet, as they said they were super busy and didn't get around to trying the flash yet.

 

Good. I'm hoping I'm the only one!

 

For those tuned by Loi, I have an update from him:

VF Tuner will add the latest ECU Calibration ID numbers from the TSB Update. Once it has been released by VF Tuner then I can provide you with an updated tune map if you decide to get the TSB Update done at the dealership.

I can let you know when the updated files are released so that you can schedule a TSB Update with your local dealership.

The tune Update once VF Tuner has released the files to me will be at no cost to you.

 

Wow, that's crazy. It makes me want to wait a little longer for the update now. Mine isn't really that bad, it just depends how quickly I come to a stop.

 

Which dealer?

 

Lexus must have shipped the dealer the ECM with an old CAL ID because all new ECMs should come with an update firmware (CAL ID).

 

Remember the TSB for the bumper seperation? The whole ziptie-gate!! Not sure I trust TSBs from Lexus these days. Unless something really breaks down, I am leaving mine alone....Had it for almost 4 years and never felt I needed my tranny looked at.

 

Hennessy Lexus Gwinnett, my usual.

 

I went out for a drive this morning and tried numerous time and could not find anything harsh at all...smooth as silk!

The only time I feel a hard shift is in manual mode in an harsh acceleration going from 2 to 3rd, and even that is not bad at all

 

I guess there are folks out there who got lucky and do not have this issue with theirs. However, for those of us who do, like me and probably most people I know who have an IS 500, we should not accept it as normal. No transmission should ever make clunking sounds during normal operation, especially in fully automatic mode in an average driving situation - gently braking and slowing to a stop at a traffic signal. Mine has been doing this as long as I can remember. I don't think I noticed it the first few days I had the car, but it's been there pretty much since week 1 of my ownership. I guess that may be why my dealership wants to get some data from the car - they could be concerned that this issue has gone on for so long so as to have caused damage. I don't know this, just reading between the lines of what they told me.

 

Went back to the dealership today because they uploaded an inspection video of my car stating that there was nothing wrong. I got the master tech to ride with me and reproduced the issue for him. For some reason, he wants to attach some sonic sensors to the car to pinpoint the source of the noise and ask Lexus engineers if this is normal.

Speaking of normal, does this seem normal to any of you?

 

Sounds like he’s not interested in touching it…period. I wonder why. 🤔

 

I don't know - I thought this is what a TSB was for! I am confused. He acknowledged the existence of the TSB but didn't seem to be convinced it was the same issue.

An interesting hypothesis he made was that the engine torque was causing it to ka-chunk into the next gear when downshifting, and that's why the fuel cut logic needed to be adjusted. It also didn't happen whenever we came to a stop when going downhill, which is something I hadn't noticed before - it only seemed to happen on level or uphill surfaces.

 

That seems REALLY weird. Why would you need a sonic sensor when the car clunks WHILE SHIFTING and jolting the whole car? Helen Keller could diagnose this issue! If they don't get the car fixed and call it normal, even with a TSB, its time for a new dealership if that's an option for you.