Could you go to a good transmission shop and pay them for a written evaluation, this might give you more clout in dealing with the dealer & Lexus.

 

Did the dealer try to reinstall the update via computer? Sometimes updates done wirelessly files could get corrupted due to interruption of the download. Installing corrupted software will definitely have an adverse affect to your onboard computer. The Lexus techs are just confirming you have the current update, and it appears that the troubleshooting stopped there. This is not an uncommon thing with wireless updates. If you have an iPhone you know what I mean. Shame on your Lexus dealer for not at least trying that if they didn't.

my2cents.....

 

I know nothing about the Special Campaign C Safety update, however when I got the update for the hesitation issue they only disconnected my battery for less than 5 minutes. On my way home I noticed that I had no sport+. My service and I went back asked the mechanic to disconnect the battery for 30 minutes, something I learned from this forum, Done and issue(s) was resolved. Don't know if this would help you.

 

Tell the asshat dealer that the car won't give you a code if the wheel falls off either, but that is no reason or excuse that there isn't a problem! Ridiculous!!!

 

I think you've might have come across in a aggressive manner so they would rather tell you to kick rocks and try and solve the issue with you. Just apologize even though you did nothing wrong, ego battles seem justified when you spent X amount of dollars. At the end of the day you really do catch more with honey rather than vinegar. I get it, I would be pissed too but an apology could change their view and perspective and they'll work with you to do a reflash, or even just hear out your complaints to see if there is a underlying solution.

But your symptoms of lag or hesitation is pretty normal to me at least. My 19 rx350 f sport has does this since day one with 2 miles on it lol. Its really apparent when your moving at a constant speed and then floor it, the rpms jump up and nothing happens for a bit till the tranny can find a suitable gear, downshift to it, and then accelerate. I've also noticed when your in normal mode, moving at a constant speed, you'll normally depress the gas the same amount as usual to softly accelerate, but the transmission wont up shift and itll bring the rpm up to around ~4k-5,500, and then violently upshift jolting you and everyone in the car. Or my favorite, when your lightly braking, the tranny will violently downshift making your foot depress the brake with some extra force whipping you and everyone in the car. I swear people who are in the car while i drive probably think I have a lead foot.

There is plenty of documentation of the hesitation or "lag" of the car and since the 8 speeds came out in ~2010 lexus has refused to fix the problem stating its normal. I agree tho, for a lexus it shouldnt drive like this and its really pathetic.
https://www.clublexus.com/forums/rx-...-159-a-49.html

 

OP: There is a workaround to the hesitation issue, and that is an aftermarket device called “Pedal Commander.” I installed one on my 2019 RX350L, and the hesitation/lag has virtually been eliminated. BTW, what we’re experiencing with the “drive by wire” throttle system is not unusual with late model cars. The install is simple and no special tools are required; plug and play. The only negative is fuel economy drops slightly (1 mpg) because the throttle plate opens sooner; the trade off is worth it IMO. The install leaves no footprint, however, if I’m taking the car in for anything while under warranty, I remove it. Cost: $330.

 

Plugs in where? OBD port?

 

My 2018 is under warranty and I leave the Pedal Commander on. The service manager warned me that I might not get the desired results from the ECU update with the Pedal Commander installed, and I told him "I'll risk it". That's the only time they've mentioned it.

@Mike, it connects between the pedal output and the connector on top of the pedal, so it's in-line with the throttle circuit. The little unit velcro-sticks to wherever you want it. Mine is by my right knee.

 

Interesting. Is the performance improvement worthwhile?

 

Welllll -- probably that's more a matter of taste than objective fact. The unit is fairly pricey by most people's standards, and the difference may be more dramatic on some cars than others. When I first installed mine, I chose a more agressive setting than I have now. It was too "twitchy". So I backed it down and now it is only a little twitchy. But it did pretty well eliminate the lag of the OEM default throttle. I was hoping it might have a positive effect on the "hesitation", but that's entirely the transmission and so it really didn't affect it. I'm happy with it, but I dunno if it was worth $275 or so.

 

Here's what we did to get 85% of the performance back so we don't hate our car anymore. It plugs in under the dash to the OBD. It does not undo the software, just over rides it. From Amazon, about $85.

Brand: Power Tune Performance

Brand: Power Tune Performance

Fits Lexus RX350 - High-Performance Tuner Chip and Power Tuning Programmer - Boost Horsepower and Torque

In the past we have fixed similar issues on other vehicles (ie Corvette or '05 GTO) with retuning by performance shops but we were unable to find any programmer for this Lexus. Quick affordable fix for something Lexus may decide to change in a few years after enough complaints or the class action lawsuits they have going on. I can tell you the difference was immediate.