Throttle hesitation

[Teleguy11]

I'm actually afraid to contact the dealer I purchased the car from about this.
Past experience with this Toyota dealership has given me the feeling that they don't want to work on this car.
I'll give them a call next week to see how open they are to update my software.

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[tjk]

Has anyone brought their car to Toyota and actually got it diagnosed and fixed?

For me, this happens when I let the car idle or warm up well past the cold start. It's really scary sometimes because I live off of a busy street and need to zoom out of my driveway with oncoming traffic.

It's really crazy that something this dangerous isn't a TSB!

Only quite the opposite experience. I tried two dealers in my area to the North of LA.
One refused to do anything unless I demonstrated the issue.
The other was more helpful but knew nothing about the car and software, they didn't know how to update the firmware.

 

[B54]

The vehicle has been updated to latest version: S18T-22-03-535.
Previous version: S18T-21-11-530.

....

EDIT: Seems to be fixed after thousands of additional kilometers driven.

While it used to happen after every few hundred of miles driven, it seems to be happening again.
However, it happens far far less often. Maybe once every 1000+ miles. More of a once in a blue moon type scenario. So if you have the same issue, the update, maybe installing an even newer one, could drastically improve the issue.

 

[wack]

May be unrelated but I think after I've set the car to sport individual mode by default (only have the engine in sport, the rest normal) I rarely had the issue.

Also, I simply changed the way I back out of the garage on that slope, avoiding one wheel getting air at all. Never had an issue when wheels stay in contact. By now I'm pretty sure it's a TC-related issue.

I was driving today and had a moment of realization, having read this thread a while ago.

I've never dealt with this issue in two different 3.0 supras, a 2020 and a 2021. BUT, I recently had a mishap with steel cords from a shredded tire wrapping around the hub assembly and slicing one of the rear wheel ABS sensors.

At the time, my brakes were screeching and I thought it was a pebble stuck in the dust shield (turns out it was front brake pads on its last legs). So I did a hard turn trying to dislodge it. The rear lost traction, ABS kicked in hard and I got the warning chime of doom, along with a handful of messages:

* Chassis Stabilization
* Rear differential lock reduced
* Parking Brake malfunction

Note, I'm not sure what happened exactly. Either the hard turn itself made the steel cord cut the ABS sensor, or the ABS sensor was already on the fritz from the steel cord but then the loss of traction triggered it to go bonkers, just like how you guys describe how to trigger your throttle hesitation issue.

And then I had basically all the symptoms you describe. Taking off from a stop, long hesitation and then if you push the throttle harder, crazy torque all at once. Except I think in my case, the car was in limp mode from the faulty ABS sensor? So it limited power and shortshifted to 5th gear. Unless that is what is happening to you guys?

But what I can take from this is that the throttle hesitation issue has to be 100% related to the ABS/wheelspin sensors going cuckoo. Is there a chance that replacing the wheelspin sensors will resolve the issue??

I think it might be a little unlikely though because it's also worth noting that you guys don't have the same warning messages I got, correct?

The one comment about cross-pedestrian traffic detection triggering it is also worth looking into. If you guys turn that off, does it prevent the throttle hesitation?

 

[Loco38SUP]

I was driving today and had a moment of realization, having read this thread a while ago.

I've never dealt with this issue in two different 3.0 supras, a 2020 and a 2021. BUT, I recently had a mishap with steel cords from a shredded tire wrapping around the hub assembly and slicing one of the rear wheel ABS sensors.

At the time, my brakes were screeching and I thought it was a pebble stuck in the dust shield (turns out it was front brake pads on its last legs). So I did a hard turn trying to dislodge it. The rear lost traction, ABS kicked in hard and I got the warning chime of doom, along with a handful of messages:

* Chassis Stabilization
* Rear differential lock reduced
* Parking Brake malfunction

Note, I'm not sure what happened exactly. Either the hard turn itself made the steel cord cut the ABS sensor, or the ABS sensor was already on the fritz from the steel cord but then the loss of traction triggered it to go bonkers, just like how you guys describe how to trigger your throttle hesitation issue.

And then I had basically all the symptoms you describe. Taking off from a stop, long hesitation and then if you push the throttle harder, crazy torque all at once. Except I think in my case, the car was in limp mode from the faulty ABS sensor? So it limited power and shortshifted to 5th gear. Unless that is what is happening to you guys?

But what I can take from this is that the throttle hesitation issue has to be 100% related to the ABS/wheelspin sensors going cuckoo. Is there a chance that replacing the wheelspin sensors will resolve the issue??

I think it might be a little unlikely though because it's also worth noting that you guys don't have the same warning messages I got, correct?

The one comment about cross-pedestrian traffic detection triggering it is also worth looking into. If you guys turn that off, does it prevent the throttle hesitation?

The only time I’ve encountered it was from trying to drive aggressive right after a cold start or a warm restart. If I let the car idle a few minutes or gradually bring the car up to speed its not a problem.

-RJM

 

[Dannyvandelft]

When it happens, just keep your throttle position. Don't mash it, let the car work it out for 2 seconds, power will come back, and you're on your way.

 

[FLtrackdays]

I was driving today and had a moment of realization, having read this thread a while ago.

I've never dealt with this issue in two different 3.0 supras, a 2020 and a 2021. BUT, I recently had a mishap with steel cords from a shredded tire wrapping around the hub assembly and slicing one of the rear wheel ABS sensors.

At the time, my brakes were screeching and I thought it was a pebble stuck in the dust shield (turns out it was front brake pads on its last legs). So I did a hard turn trying to dislodge it. The rear lost traction, ABS kicked in hard and I got the warning chime of doom, along with a handful of messages:

* Chassis Stabilization
* Rear differential lock reduced
* Parking Brake malfunction

Note, I'm not sure what happened exactly. Either the hard turn itself made the steel cord cut the ABS sensor, or the ABS sensor was already on the fritz from the steel cord but then the loss of traction triggered it to go bonkers, just like how you guys describe how to trigger your throttle hesitation issue.

And then I had basically all the symptoms you describe. Taking off from a stop, long hesitation and then if you push the throttle harder, crazy torque all at once. Except I think in my case, the car was in limp mode from the faulty ABS sensor? So it limited power and shortshifted to 5th gear. Unless that is what is happening to you guys?

But what I can take from this is that the throttle hesitation issue has to be 100% related to the ABS/wheelspin sensors going cuckoo. Is there a chance that replacing the wheelspin sensors will resolve the issue??

I think it might be a little unlikely though because it's also worth noting that you guys don't have the same warning messages I got, correct?

The one comment about cross-pedestrian traffic detection triggering it is also worth looking into. If you guys turn that off, does it prevent the throttle hesitation?

She’s definitely got a lot of brains internally. I’ve had both of those 1st two codes. Thanks to everyone‘s help on here 1) I got an independent BMW mechanic 2) got two aftermarket coders for this car. When the two of them unite = Wonder Twin Powers Activate (really old cartoon, don’t mind me)

So I’d highly recommend the both. You might even get lucky and find a mechanic that has all the unlock tools (like the junkyard coders do).

 

[Motorknut]

Toyota has already confirmed there is a software update to address a throttle hesitation issue.

BMW already had this in the works for the Z4. and makes sense the Supra is affected too.

The challenge is getting your local Toyota dealer to get it done for you. I had to kick a fuss for months before my country authorized dealer finally pushed HQ and got an answer. Toyota has an escalation process where they require proof of the issue, and that’s why this particular issue (which is intermittent with no error codes) was not initially addressed properly.

We get zero direct support from Toyota outside of Japan, and rely on the AD for help. If you can contact Toyota USA and remind them of the safety implications , you should hopefully get better responses.

one thing I hate about the Supra is the Aftersales support. BMW SIBs seem pretty straight forward, but there’s some weird trickle down from Toyota.

 

[HACKRCHILD]

Hi everyone, you may find this interesting. I have had the latest update from Toyota for this and it reduced the issue significantly but still comes back once in a blue moon as others have reported.

However @Crimzon_Skyz gave some interesting information. You can read the thread here: https://www.supramkv.com/threads/ho...ar-for-throttle-hesitation-issue.19110/page-5

Here’s the import bit however:

“
My update & guide for anyone interested:

So as i previously mentioned, I went into Listers Stratford-Upon-Avon and spoke to their Supra tech Chris. I decided to go the official route and state the real issue. Obviously he couldn't recreate the issue as its so random but suggested due to my safety concerns that he raise a ticket with Head office who would work in tandem with BMW on the issue. My car was there for the best part of a week while they went back and forth.

I was told my car was on the latest update that Toyota had available: S18T-21-03-XXX (last 3 digits unknown). After the tech spoke with head office and BMW they confirmed that BMW had encountered the issue on the Z4 and had a much newer software update available but Toyota dont have access to it. The BMW Engineer worked with my tech to update my car with the BMW module updates bringing it to software version: S18T-23-07-505.

As of writing this I have no idea if this has indeed solved this issue but have an appointment with Toyota in a couple of weeks to report any findings. Based on this info and I'm sure other cars having this fix issued to them Chris was confident it wouldn't be too long before BMW passed this set of updates along to Toyota for official release. As you can see its a huge software jump in iterations so fingers crossed this fixes it and gets issued for everyone to benefit from.

Sorry for the long post, I just wanted anyone chasing this to have all the info possible. If you go in for the update right now I think the truth is the tech will be correct in thinking your car is on the latest update but in actual fact Toyota dont have it.”

Basically the latest Toyota update (at least in the UK) does NOT have the fix. However it seems bmw can update your modules to resolve the issues. I assume if you wait, this will roll through to Toyota eventually.

 

[CarGuy11]

^^^ Thanks for the version #! Since this updates every module in the car have you felt any other differences since you received this (steering, suspension, headunit, etc)?

 

[HACKRCHILD]

^^^ Thanks for the version #! Since this updates every module in the car have you felt any other differences since you received this (steering, suspension, headunit, etc)?

I have personally noted quite a few differences in my car. I made note of a few on the thread I previously shared.

 

[MoosieMoosie]

Hey guys, my car is also doing this now at 5.4k miles. I noticed the problem only appears after a cold start and only when i am coming out of my drive way (3 wheeling out due to angle). Notice in the video the drive mode has not changed but the way the rpm comes up is drastically different even tho the throttle input is the same. Also, something that wasn’t caught on the video, when I pressed the throttle harder, the car will drop rpm so much that it’s almost Stalling out. I believe in my case, the traction control system is most likely the main problem lol. Sorry if this has been deduced already, but just giving out my piece of evidence

 

[tjk]

Hey guys, my car is also doing this now at 5.4k miles. I noticed the problem only appears after a cold start and only when i am coming out of my drive way (3 wheeling out due to angle). Notice in the video the drive mode has not changed but the way the rpm comes up is drastically different even tho the throttle input is the same. Also, something that wasn’t caught on the video, when I pressed the throttle harder, the car will drop rpm so much that it’s almost Stalling out. I believe in my case, the traction control system is most likely the main problem lol. Sorry if this has been deduced already, but just giving out my piece of evidence

Kudos for capturing it.
I also have a video of the whole process - backing out of the garage, catching air with one wheel and almost stalling after. And I learned to replicate it if I needed to. 100% has to do with one wheel hanging. Gotta be some safety feature.

 

[PMIRO2]

Just came across this thread as it happened to me 2x this past weekend. 21 3.0 with just under 5k miles. Both times were after I had driven briefly, turned off the car, sat for 20-50 minutes, then drove again. Both times from a dead stop. Not going to lie, but it was pretty scary. First time was making a right onto a 3 lane road with someone coming in my lane behind me. Second time was making a left across the same three lanes with multiple cars coming at me. I did as others mentioned and let off the gas pedal a bit until it caught up.

 

[KBGT]

Question for all the people experiencing this issue, does it happen with VSC off? Basically is the stability control system pulling torque then ramping it back to normal?

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