Hybrid module/Transmission - New Issue Toyota hasn’t seen before

[taystaco]

Hey yall

New to the board but been lurking since I got the truck.

Wanted to inform the group about a hybrid system transmission issue that affected my 2024 TRD OR Hybrid.



For background, the truck was purchased used in March of this year with 400 miles, I’ve essentially owned it since new. It had its first oil change at 1,000, another at 5,000, and then one at 10,000. I had actually scheduled the 15k service when the issue started. I would say my driving style is normal, sometimes I drive fast, sometimes I take it easy.



On Sunday 9/14 the truck made a loud electronic/ metallic screeching sound and a thunk. The sound was kind of like a siren. After that the truck would lurch every time you came to a complete stop (engine turns off) and began to accelerate again. Engine turns on, begins to move, THUNK, then drives like normal. (Video attached)



The truck did not display any warnings on the MID or a check engine light.



I brought the truck in on 9/16 (didn’t drive it on 9/15) and the service dept informed me that the truck had some kind of transmission issue that Toyota hadn’t seen before. They sent a message to Toyota corporate and had engineers on the phone walking them through troubleshooting the truck.



After teardown, the techs/engineers found that the hybrid motor had failed, which caused the transmission to fail also. They found metallic debris in the transmission and trans cooler.



The dealer opened a case with Toyota and the truck was fixed under warranty— I just got it back today 9/30 and it seems like it’s good as new.



I wanted to post this in case anyone else has the issue as well- hoping it was one in a million for all our sakes.

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[TacoFreak]

Thanks for the heads up. You would think that a hybrid motor failure would be rare, or at least I am hoping it is.

 

[TFOUTS]

I’m guessing this is an isolated incident

 

[TacoFreak]

You've got to love how when our vehicle break the dealers drive another truck to see if it is normal. Fingers crossed because maybe they are all F'd and we don't have to fix this one. Oh what a feeling!

 

[taystaco]

I’m guessing this is an isolated incident

Hoping so as well

 

[taystaco]

You've got to love how when our vehicle break the dealers drive another truck to see if it is normal. Fingers crossed because maybe they are all F'd and we don't have to fix this one. Oh what a feeling!

Yeah you can tell from the video the truck like jumped?? Hated to be the bearer of bad news but cars aren’t supposed to do that hahaha

 

[lauren01]

This jumping transmission happened to me today. Truck was reporting hybrid system failure and every code in its dictionary :( . Ugly… see pic for summary.
We are just over 2500 miles with oil changed at 1500.

We were driving through moderate to heavy rain for two hours in our ‘25 Trailhunter on a California freeway, weather in low 60s, not windy, not high elevation, about 1200’ highest.

We limp moded ourselves to a nearby Toyota dealer, an hour from home. They will call me Monday once they can check it out. Kindly friend picked us up.
&(#^bc$”@/-!!

 

[Baltimore]

If I combine information from other posts, it's not that the hybrid system fails first. The transmission fails, but the hybrid motor shares oil and thus takes on downstream damage as a result.

I could be totally wrong but looking at the TSBs plus that video of the hybrid motor breakdown has me speculate that way.

 

[TacoFreak]

Unfortunately these are the kind of messages a lot of people have seen when their 4th gen transmissions die. There are other possible causes too if I remember correctly so keep your fingers crossed. Good luck and keep us informed!

 

[lauren01]

Thanks, makes sense. Glad I kept my ‘23 Integra 6-speed manual.

 

[lauren01]

Update: I have my truck (2025 Trailhunter) back with a reflashed ECU.

Toyota technician pulled code P21199B (Confirmed Short) associated with throttle actuator A, as shown on the report and warranty receipt provided (pics attached). This is one of the known causes of the truck going into limp mode.

However, the techs did not identify a specific short, but so far the Service Advisor has said it seems like there was low voltage, but I no need to talk to the Foreperson who was not in today. A message has been left for him to call me tomorrow.

Their test report indicates that the battery
voltage tested at 14.0, 14.1 and on the warranty receipt paperwork 14.3 v is printed at the top. @TacoFreak any thoughts on that?
Might an Optima yellowtop be good to get? I was planning to get one anyway.

Google AI for what it’s worth indicates the following.

The Toyota Tacoma error code P21199B indicates a throttle actuator control system problem, likely a "throttle body range/performance" issue. This means the engine's computer (PCM) has detected a problem with the electronic throttle control, causing the vehicle to enter "limp mode" (reduced power) for safety. Common causes include a sticking or dirty throttle body, a faulty throttle position sensor or accelerator pedal position sensor, or problems with the throttle actuator control motor or associated wiring. [1, 2, 3, 4]

Common causes for the P21199B code:

• Throttle body issues: A dirty or sticking throttle plate or linkage can cause this code.
• Sensor malfunction: The throttle position sensor (TPS) or the accelerator pedal position sensor (APP) may be faulty.
• Wiring and connector problems: Corroded, damaged, or loose connectors and wiring for the throttle system can trigger the code.
• Throttle actuator control motor: The motor that controls the throttle plate may be defective.
• PCM failure: In rare cases, a faulty Engine Control Module (ECM) could be the cause. [1, 2, 5]

What to do if you get this code:

1. Reduce power and drive cautiously: The vehicle is likely in limp mode, so you will notice a significant lack of power. Drive slowly to a safe location to diagnose the problem.
2. Check for a clean throttle body: A simple first step is to clean the throttle body. This may provide a temporary fix if the issue is just a dirty plate, but it might not be a permanent solution if a sensor is bad, say users on JustAnswer.
3. Inspect wiring and connections: Check all wiring and connectors related to the throttle body and pedal assembly for any signs of damage or corrosion.
4. Replace faulty components: If cleaning doesn't work, the next step is typically to replace the throttle body assembly, the accelerator pedal assembly, or any other faulty components identified during diagnosis.
5. Consult a professional: If you are not comfortable diagnosing and repairing these components, it is best to take your vehicle to a qualified mechanic for diagnosis. [1, 2, 4, 5, 6]

AI responses may include mistakes.

[1] https://www.kbb.com/obd-ii/p2119/

[2] https://www.yourmechanic.com/articl...hrottle-body-range-performance-by-robert-kulp

[3] https://charm.li/Toyota/2009/Tacoma...)/Testing and Inspection/P Code Charts/P2119/

[4] https://partsavatar.ca/p2119-obd-ii-trouble-code-throttle-actuator-control-body-range-solution-plate-position-sensor

[5] https://www.justanswer.com/uk-ford/3i9d2-problem-throttle-body-work-car-went.html

[6] https://partsavatar.ca/p2119-obd-ii-trouble-code-throttle-actuator-control-body-range-solution-plate-position-sensor

 

[TacoFreak]

However, the techs did not identify a specific short, but so far the Service Advisor has said it seems like there was low voltage, but I no need to talk to the Foreperson who was not in today. A message has been left for him to call me tomorrow.

Their test report indicates that the battery
voltage tested at 14.0, 14.1 and on the warranty receipt paperwork 14.3 v is printed at the top. @TacoFreak any thoughts on that?
Might an Optima yellowtop be good to get? I was planning to get one anyway.

First off congrats - it is not a failed transmission, which is great news!

Hopefully the service department will figure out why the there was a low voltage reading, but I don't think it was caused by your battery. Those reading sound like what I would expect when the engine is running, and seem normal to me. The real question is what caused the system voltage to drop so low that it threw a code, and the tech doesn't seem to know. Maybe you will find out more when you talk to the service manager, and maybe it will take some time to track the problem down. So they basically told you the voltage was both normal but also low enough to put the engine into limp mode. Obviously there is more going on than they know at this point.

Good luck and keep us in the loop.

 

[lauren01]

First off congrats - it is not a failed transmission, which is great news!

Hopefully the service department will figure out why the there was a low voltage reading, but I don't think it was caused by your battery. Those reading sound like what I would expect when the engine is running, and seem normal to me. The real question is what caused the system voltage to drop so low that it threw a code, and the tech doesn't seem to know. Maybe you will find out more when you talk to the service manager, and maybe it will take some time to track the problem down. So they basically told you the voltage was both normal but also low enough to put the engine into limp mode. Obviously there is more going on than they know at this point.

Good luck and keep us in the loop.

Thanks a bunch for your input. I am also relieved not to have a new transmission and probably engine if it had trashed it.

One thing that was assuring is that they mentioned this is in their system; there is a report into Toyota about it. I also saw a TSB referenced in the paperwork, so this appears to be a known occurrence.

I’m going to take a lot of test drives and try to be not far towing / limping from the two Toyota dealers in my area.

If I lived near the Car Care Nut, I would ask him to take on the challenge of finding the culprit.

Shower thoughts: Assuming I get the Optima AGM battery, will the truck’s voltage meter be able to capture accurately what it measures? I see on the dash, the meter range 9 to 19. Is this going to lead me down a rabbit hole of additional instrumentation?

 

[coldtaco]

Mine would have the rpms either stop at 2000rpm while idling down or if at idle coming to a stop idle up to 2000rpm. If I blip the throttle it would idle back down. Dropped it off at the local dealer since I was going to be out of town for two weeks. When I got back the shop foreman said that they replaced the throttle body due to odd/non normal electrical readings. I haven't been able to reproduce it since. I do have a feeling like the engine is lugging since the transmission would go into 7th gear at around 1300rpm. He said he can't really do anything about that unless Toyota comes up with a new calibration. Got a OTT tune yesterday and it seems to have helped reduce this feeling some.

 

[lauren01]

Thanks this will help me quiz the foreperson assuming I get the chance to talk to him.

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