OFFICIAL: MY22+ Toyota Tundra - Throttle Lag/Hesitation From Stop Issue(s) - T-SB-0111-22

Anyone make any progress with toyota on acknowledging the throttle lag? My '23 has had these issues ever since purchase date. The most the dealer has done for me is flash the ecu which didn't do anything.

 

The TCM update for the "Unexpected Vehicle Movement" has helped some, but it is not entirely gone.

 

Is there a way to recalibrate the throttle body that would improve response to the pedal?

 

I'm reading though the class action filled the other day https://www.classaction.org/media/daley-et-al-v-toyota-motor-north-america-inc.pdf

It seems more the complaintants are actually having *THIS* issue and not a blown engine issue.

 

That was a super interesting read. Thanks for sharing.

 

yes, most people are tying that to the engine bearing thing, this lawsuit is way more about the throttle lag surge thing

 

I have the throttle delay when the engine is cold. Once warmed up it acts normal... Wait that may be me too.

 

Add me to the list of those experiencing throttle lag / hesitation, or as I call it, a dead gas pedal. I've almost been hit twice because of this issue.

 

Sadly, same here. Sport mode makes it almost a non-issue, but I don't typically drive around in sport mode. Would be nice to have a fix.

 

Oddly enough, I only drive in Sport mode and all 3 occurrences for me have been while using sport mode.

 

Perhaps Toyota should consult with NASA like they did with the runaway Camrys?

 

I have the pedal delay too. Only notice it when the engine isnt up to temp yet.

Give a bit of gas at a stop sign when the engine is cold and its a 1 Mississippi, 2 Mississippi event.
Hate to say I am used to it but yeah I am.

 

I wish mine was only when the engine was cold. Last time this happened I had used remote start to warm it up for 10 minutes, drove to the gas station and then when leaving the gas station it happened.

 

I've not done much active research on this recently. But here is the peices I have so far.

I think cold temps are a factor but not the only factor. I kinda think the cold temps are a reason the issue is again comming up a lot.

I got access to the most recent TIS tech docs about reseting and learning on the transmission. The process is actually pretty complex.

I think reseting the Trans memory (A/T Compenstation mode makes things worse). Toyota mentions the proper procedure is in TIS to set a "Fixed" A/T compensation Code:
Powertrain / Transmission /Utility/ A/T Code Registration (Fixed Code).

This is mentioned in document AJA0E Automatic Transmission System: Registration. The document mentions when the A/T Compenstation code is not known, to reset it with the "Fixed Code"

The other tech doc AJAOE Automation Transmission System Initialization, they mentioned the proper drive pattern to commenence TCM learning:

Conditions the ATF temp needs to be 122 to 176F
A scan tool is needed to see the acclerator % as specific acclerator inputs are needed.

One accel pattern the accelerator needs to be held exactly in the 15 to 20% range, you must get above 6.22Mph and get to the maxium speed possible holding the pedal at that %. Then Slow down to 3mph with steady brake.
The 2nd pattern is the same as above but the accelerator between 25% and 35%

Each time the pattern is preformed you must come to a complete stop before trying again.

S-mode decelleration pattern:

You must get above 18.65mph and then get into S6 for 4 seconds, then slow down steady while stepping down each gear for approxmately 2 seconds.

The doc is a little confusing because they mention the "hightest speed possible" but not exact speeds besides the miniums.

But I take it if you don't drive with holding the pedal steady in those exact ranges, learning is probably never happening.

Doing all this may reduce but not elimante the delay.

 

Thank you @rlc177 for that post. That does seem really complex and I'd agree given that data, it seems the likelihood of completing the learning process is just above a non-zero chance..

 

I had this for about the first year, at some point I had some kind of update done, ecu thing maybe and never really thought about it but the lag thing has not happened in a very long time, maybe a year or so. Or it could be I’ve driven it for two years and 66K miles and the truck figured it out ha ha.

 

I had my first service the other day and when I got the truck back, the hesitation was gone. The service advisor didn’t mention doing anything other than the typical inspection (and I added an oil change at the 5K). There was nothing mentioned on the paper work as to any “reset”. But mine had a significant delay between about 0 and 25 mph since I bought the thing, and now it’s pretty much gone.

 

I sure hope mine goes away as well! Unfortunately, until Toyota confirms it as a real issue and explains it or provides a fix, I'll never trust it won't be back to haunt me again when pulling out into a busy intersection. I went 6 months between occurrences with the most recent happening about 3 weeks ago.

 

I found this link among the various facebook posting about a firm doing and investigation on this.

https://www.ahdootwolfson.com/blog/...itation-from-stop-class-action-investigation/

This is a different frim than the other class action filed in the news.

 

Very interesting and thank you for sharing. I have yet to have the acceleration surge when I experience the issue, just a dead gas pedal. What I don't know is if I've just been lucky and been out of the gas when the truck woke back up or if mine isn't prone to that symptom.

 

I think the surge is from people not letting off the pedal before the truck accepts the input. My truck does the lag bad. Worse when cold/1st started. I have a stop sign about 1/4 to 1/2 mile from my house. I'm in gear probably within 30 seconds of starting my truck. If I don't completely stop for 2+ seconds, when I push the gas, the engine doesn't respond right away. It's second nature for me to let off the gas and press again. It usually goes by then. In testing, I've not completely stopped but almost. Like at a yield sign where you look and realize nothing's coming so you let off the brake and back on the gas. Press maybe 1/3 throttle. The engine for a millisecond might blip the tach but for the most part is unresponsive. I'll keep my pedal where it's at and after 1-2 seconds, it'll start to accelerate and then match throttle input and spin a little. To which I let off the gas then. Sorry for the novel.

 

Odd it keeps being mention about debris as it pertains to this, it’s clearly two separate things

 

Yeah totaly not a debris issue, I think most likey an ECU/TCU software defect, but there could be an issue with the transmission solnoid sticking or something like that. Feel like the people at Toyota that understand the drive train control and software should be able to know "what to look for"

 

Agreed, these classes action lawsuits appear to be convoluting 2 separate and unrelated problems.

To me, it invalidates the lawsuits, but I'm not an attorney.

Thankfully, I've never experienced the throttle lag in 20K miles. Hope it remains that way. And I hope those who do experience it find a resolve.

 

I wish I could reproduce the issue like you can. I've working with Toyota and the dealership for a few weeks now on this. Hard to get any traction when I can't reproduce it and it happens so infrequently.

 

I thought the same thing.

 

I have the lag as well on my MY24 non-hybrid. It almost seems as if the tranny hasn’t completely shifted into 1st so when I make a quick stop and decide to go again… it’s not in gear… then drops into gear and off she goes. I’ve learned to feather the pedal to prevent my head from snapping back but it’s not a great user experience.
Sudden acceleration (2007ish) and now lack of … why can’t Toyota get their $hit together. My F150 was a quality nightmare but at least had the acceleration part correct.

 

It's a problem that only affects a fraction of Gen 3 Tundras. The vast majority don't have the problem.

I'm sure that's part of the reason why Toyota is having trouble figuring it out.

 

If you are riding along with a tech, see if they can have techstream hooked up.

The best I can figure its a specific NT Speed and Output Shaft Speed when the ECU commands 1st gear.

You have to watch the data stream as the truck slows down, you want to hit the gas somewhere where after the ECU commands gear 1 (SW Status) and the NT speed sensor is reading 150 RPM and the output shaft speed is reading 50.

The problem is the 2 values are only in 50 RPM increments so the exact RPM's are not known. Its a thread the needle situation for sure.

I can say if you nail NT speed 150 Output shaft speed 50, about 1/2 second after the shift to 1st there is always some sort of delay, but its sometimes short.

(PIDS:
NT Speed Sensor RPM: Speed of Transmission input shaft
Output Shaft Sensor RP: Speed of the Transmission output Shaft
SW Status: ECU Commanded Transmission gear)

In techstream these data pids may not be selected as default, they are under the "AT" Preset.

 

Thanks for the information. I already rode with the tech and we only hooked up Techstream after the ride to look for any logs from the previous event 3 weeks ago, no issues during the ride-along of course. If I get another ride-along though, I'll see what I can do.