[Turbocat9000]

On my 2018 SE (US made) I had the dealer install T-SB-0152-19 a few years ago. At first it seemed like there was some noticeable improvement. But after a while the original transmission problem returned. These days there is a MAJOR hesitation on acceleration from a slow roll or rolling stop. When I hit the gas there's about a 2-second delay until the car takes off. I've learned to deal with it because like I said everything else about the car I like.

If the TSB was done correctly, it's a permanent fix. I had mine done at 10K and it's still great at 50K. It sounds like your dealer just cleared the memory and let it re-learn.

 

[Turbocat9000]

Well I wouldn't put anything past a dealership but that's a little hard to believe that dealer service departments are doing that. Why would they blow off doing a TSB, when a TSB doesn't cost them anything, and just clear the memory instead? Plus, in the immediate weeks/months after my visit to the dealer the problem was no longer occurring. It just resurfaced some time later.

Customer brings car in and complains about poor-shifting transmission, which could be one of many different things. Customer doesn't mention the TSB, or the advisor doesn't document it during check-in. Tech clears the shifting memory so it can re-learn the driver's habits. Driver notices improved shifting, temporarily (I don't know how long the supposed transmission shift learning takes).

TSB-0152-19 involves flashing a new calibration file to the ECU, and the last step of the TSB instructs the tech to document it with a sticker here. I'd say this is the only way to know for sure that the TSB was done correctly.

I printed the TSB out and brought it with me: https://static.nhtsa.gov/odi/tsbs/2020/MC-10173797-9999.pdf

 

[Turbocat9000]

A faulty TPS (Throttle Position Sensor) could be the root cause of this common 8th-gen transmission problem? I hadn't heard that.

Someone should let Toyota know.