5th Gen Brake Failure - 17 TRDP

[BlackWorksInc]

100% agree with your thoughts. Toyota did identical replacement with my 4Runner. I think they know there is something definitely happening and they are trying to figure out what it is before it becomes a huge public issue.

It's possible, the whole process is pretty long from identifying a possible issue/defect to it becoming a TSB or even a Recall. One or two oddball failures does not constitute cause for a TSB/Recall and are often calculated in production projections when vehicles are made (in fact the NTHSA won't bother with a low number of incidents until a clear pattern/defect can be isolated) and that's why we have warranty, it's all a numbers game. You'd be surprised how "big" an issue has to get before the government forces a company to do a recall, most of the time the companies self-report because it reaches a larger than projected/acceptable number of common failures for their own internal quality control. Sorta the same deal about how much foreign debris, human tissue, and biohazards are allowed in food before it becomes a health hazard.

So it sounds like they went through the usual process and documented everything to keep track of how many more times it occurs and if it's something to be worried about. As far as I can tell, there isn't anything regarding the 4Runner at the moment; Camry, Highlander, Sienna, and Tacoma seem to have something in the works; but I'm assuming that's going to be a narrow production run on the units from the supplier who makes them.

In the end it could just be that the FTS authorized a replacement just to satisfy the customer even though they couldn't find anything wrong. I've had that happen a couple times, they just say "well nothing's wrong with it, just throw a new one in to make them feel better rather than fight them on it." It's not common but it does happen.

Post Note-

Sorry if that comes across a bit dismissive, I was just trying to point out that there really isn't a conspiracy theory or anything.

 

[Izzi75093]

This just happened to me last night. No pedal, no brakes. Turning in to gas station parking lot and fortunately was only about 25-30 mph and didn’t hit anyone. Did the ntsb thing and notified Toyota. Plan on taking it in as soon as I have time to waste. No leaks, full reservoir and the brakes worked fine for my 1 mile trip home from the store. Very freaky deal

Have a 17 TRDP and yes experienced a complete brake failure. No alarms, No warning lights.....just a pop from the brake unit and the pedal went to the floor. Fortunately able to stop by pumping the brakes giving me some pedal, using the emergency brake and downshifting transmission. Very Lucky as rolled into center of 4 way stop until I stopped!

Anybody have information or experience on this? As mentioned, was able to pump pedal to get some braking. Would then hold it and it would fade back to floor.

Vehicle is at dealer now. Of course they say all is well.....but they did mention they downloaded codes consistent with a braking event? I told them it was a complete Master Cylinder failure.......anyhow, also told them to find the issue and fix it as I would not get back into the car until they repaired it

 

[keph13]

(Sorry if this was discussed in another thread and I missed it)

Does anyone know what controls pedal feel? That is, is the link from the pedal to the cylinder purely mechanical/hydraulic? On the other side, I assume ABS works by closing a valve to an individual caliper when it wants to "release" the brakes? The fact that we have brake assist seems to imply that there's at least one more piece of the puzzle.

Mostly, it seems to me that if this was caused by ABS incorrectly triggering on all 4 wheels, then the pedal would have become impossible to push instead of going to the floor, because with the ABS valves closed there's nowhere for the fluid to go? But I'm just taking relatively uneducated stabs in the dark, mostly for my own curiosity.

 

[CutthroatSlam]

Just received call from dealer.....about went as expected. Drove your car for 100 miles, checked entire system and could not duplicate issue-Brakes fine. Asked why the codes for pumping brakes? I explained during the entire event, I did not have any warning lights or alarms, but something triggered the code for brakes pumping--maybe ECU is failing? Crickets.........

So here is where we are. They want me to come and get the vehicle. Business travel prevents me from doing this until Thursday. I told them I want a complete list of all brake diagnostics with a road check noted on service invoice as well as statement brakes are functioning correctly.

Not happy with this. Now the burden is on me to record any further brake events----- guess I will keep cell phone ready on video to record if further brake issues occur.

Let's hope its not after I'm involved in an accident.

Up for some extreme offroading in Moab?

 

[epjfsa]

(Sorry if this was discussed in another thread and I missed it)

Does anyone know what controls pedal feel? That is, is the link from the pedal to the cylinder purely mechanical/hydraulic? On the other side, I assume ABS works by closing a valve to an individual caliper when it wants to "release" the brakes? The fact that we have brake assist seems to imply that there's at least one more piece of the puzzle.

Mostly, it seems to me that if this was caused by ABS incorrectly triggering on all 4 wheels, then the pedal would have become impossible to push instead of going to the floor, because with the ABS valves closed there's nowhere for the fluid to go? But I'm just taking relatively uneducated stabs in the dark, mostly for my own curiosity.

The most basic ABS system is a series of solenoid valves AND a hydraulic pump which generates the pressure necessary for braking, with the valves opening and closing to pressurize (in the case of a 4 channel system) each caliper individually.

Our system is definitely not so traditional, and I'm not exactly sure how braking assist works in lieu of a more traditional vacuum booster. This same or similar braking system is installed on many other Toyota trucks, including the last-gen Tacoma. I would be curious to know if this problem happens in those vehicles and, if not, perhaps there's a software issue unique to the 4runner.

 

[JClay]

Completely different from dealership warranty repairs. Car repairs don't have travel costs involved. Dealers do not lose money on automobile warranty repairs, they just make less than doing repairs for paying customers.

Time and time again this has been proven to be true. The people that really suffer from warranty work are the mechanics.

 

[BBToy]

I had the same brake failure occur in my brand new 2021 4R TRD OR premium, at 3600 mil. Hauled to the dealer and they can't replicate it, no leaks and no error codes were found. Submitted a Task Case with engineering and They are refusing to diagnose it any further. How did you get Toyota to take you seriously and fix your brakes?

 

[og556]

I had the same brake failure occur in my brand new 2021 4R TRD OR premium, at 3600 mil. Hauled to the dealer and they can't replicate it, no leaks and no error codes were found. Submitted a Task Case with engineering and They are refusing to diagnose it any further. How did you get Toyota to take you seriously and fix your brakes?

The disturbing thing I am seeing is if you spend a few minutes googling this issue, it looks like it is not uncommon.

It seems the constant variable is 4Runners equipped with ATRAC. The thought of this happening, especially at high speeds with family in the vehicle, is disturbing.

 

[Quentin]

The disturbing thing I am seeing is if you spend a few minutes googling this issue, it looks like it is not uncommon.

It seems the constant variable is 4Runners equipped with ATRAC. The thought of this happening, especially at high speeds with family in the vehicle, is disturbing.

I believe all 4WD 5th gen 4Runners have ATRAC.


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[TRD-Bro]

It's been 4 years since this thread started, how has Toyota not addressed an issue this dangerous?

Extremely worrisome to hear that it can happen randomly at any time, I use the vehicle for road trips to Lake Tahoe with my family and cannot imagine having total brake failure coming down those mountains.

 

[og556]

It's been 4 years since this thread started, how has Toyota not addressed an issue this dangerous?

Extremely worrisome to hear that it can happen randomly at any time, I use the vehicle for road trips to Lake Tahoe with my family and cannot imagine having total brake failure coming down those mountains.

Great question. It sounds like the techs who diagnose these types of issues are unable to troubleshoot it due to no codes being stored when the event occurs. Definitely a terrifying prospect as we are in the mountains as well almost every weekend.

 

[Hadelson]

I had the same brake failure occur in my brand new 2021 4R TRD OR premium, at 3600 mil. Hauled to the dealer and they can't replicate it, no leaks and no error codes were found. Submitted a Task Case with engineering and They are refusing to diagnose it any further. How did you get Toyota to take you seriously and fix your brakes?

I was polite the entire time. Documented everything. When the first told me the could not find anything wrong, polite response was "not taking the car off your lot. How would you feel knowing I was driving behind you and your family"? Told them they would be hearing from my lawyer. This finally got the attention needed and brought in several techs. We test drove the car with it synced to a computer and they downloaded everything recorded in the OBD.

They never found the issue, but did note the codes showing excessive brake pumping when event occurred. Based on this, they authorized and replaced the entire system.

Happy to report no further issues to this day.

 

[ElectroBoy]

This topic jogged my memory of a similar incident I had a little over two years ago. Driving my 18 ORP at highway speed a car pulled a bone head maneuver cutting across multiple lanes right in front of me in my lane then slowing down quickly for a traffic light.

I jammed on the brakes hard, moving quickly from gas pedal to brake, and really needed to lock the wheels up hard. But nothing really happened. It seemed like the ABS kicked in a little and gently pulsed the brakes with a squishy feel to the brake pedal. I would have hit the guy but since he was traversing across my path right to left he got out of my way just in time. It felt really wrong how the truck responded like that, but it was relatively new so I thought I just didn’t understand how the ABS or ATRAC was supposed to respond.

It’s never happened again in the 2+ years since. But I’ve also never been in another panic situation like that either.

 

[flippedcracker]

I had a 2012 that this happened in. Brakes just totally went out. No lights or warnings, just no brakes. Luckily I was going slow, and downshifted worked the parking brake until I got stopped. Towed it to the dealer and they told me they didn't find any issues, but replaced the master cylinder anyway. A few months later, it happened again. Towed it to a different dealer and they told me they couldn't find anything wrong. But I traded it in that day, for a 16. There was no way I was driving that car again. Haven't had any issues with any of the 4runners I've had since though. No idea what the problem was.

 

[BBToy]

I was polite the entire time. Documented everything. When the first told me the could not find anything wrong, polite response was "not taking the car off your lot. How would you feel knowing I was driving behind you and your family"? Told them they would be hearing from my lawyer. This finally got the attention needed and brought in several techs. We test drove the car with it synced to a computer and they downloaded everything recorded in the OBD.

They never found the issue, but did note the codes showing excessive brake pumping when event occurred. Based on this, they authorized and replaced the entire system.

Happy to report no further issues to this day.

Thanks for the response! Glad to hear your vehicle had no more problems after the entire system was replaced. Did they also replace the electronic components, sensors as well? Did you get any feedback on what exactly caused the failure?

My 4runner has been at the dealer for a MONTH and I was just notified yesterday that they intend to have a tech come and look at it. I will not drive it knowing the brakes could fail again. Its been a long frustrating month!

Thanks again for the response. Sounds like there are several other 4R owners on this thread that had the same thing happen....with the same brake system replacement. Wonder how those vehicles are doing now?

 

[Rpede]

This must be the electronically controlled pump leading into the master cylinder!! There are other reports of people have this problem with 4runners and FJs too. This is scary crap and can happen at any time regardless of mileage.

 

[og556]

This must be the electronically controlled pump leading into the master cylinder!! There are other reports of people have this problem with 4runners and FJs too. This is scary crap and can happen at any time regardless of mileage.

It would make sense this is something electronic based on the fact they can't find any issues with fluid levels or physical signs.