ABS on this truck is dangerous...

In that case how do I get banned? Iwanna go to mars!

 

But mars man!

 

Whenever you install tires (or anything for that matter) that far outside the engineering criteria of any vehicle there can be unintended consequences. Our IFS trucks just weren't designed to accept 3" lifts, 33" and taller tires, or tires over 10.5" wide. Sometimes it works fine and sometimes you get vibes, rubbing, alignment issues, and strange behavior with the computer controlled systems like ABS. Caveat emptor.

 

Because of payload cost restrictions, you get sent one matchbox sized chunk at a time. The whole process could take years.

 

I think the best way to describe the ABS is inconsistent and unpredictable. I've owned this truck for 7 months and had the no stop issue happen 2 times. The last time this happened I was commuting in stop and go traffic for close to 2 hours going around 5-10 MPH. I applied the brakes hundreds of times that morning and only had the one instance where the truck wouldn't stop (coasting or floating along as others have said). Today was another snowy day and I tried to get the truck to recreate this issue and couldn't by using 2H, 4H, slamming the brakes, lightly applying the brakes, etc. Most of the times the tires would actually lock up like I didn't have ABS at all. Its very strange. For all of those that say its just the tires, trust me its not the issue. Obviously better tires will grip better and not require the ABS system to activate but its still the same ABS system which will eventually have an issue again it will just be less frequent.

 

In that case for me decades! I still want in

 

Hmm, sounds familiar! I should add that I've tried to reproduce the issue on a couple different occasions also, but haven't been able to either. Last time it happened to me on the road; I went back out within a couple hours in pretty much the same conditions and just couldn't get it to happen. Truck stopped right away every time at the same low speeds and on various snowy surfaces.

 

Yes, ABS is supposed to modulate the brakes, but in two instances they released the pressure on my brakes (2005 Tacoma): 1) The brake pedal went to the floor and the brakes released when I was rock crawling; 2) During a panic stop, the brakes released when the speed went down to about 15 mph, causing the vehicle to smash into the vehicle in front of me. On #1, modulation would not have helped. Would it in #2? I don't know.

 

I agree one hundred percent with disabling ABS during Off Roading. Computer controlled safety features design for pavement aren't a good idea when off road for sure. As for #2, if the brakes are releasing totally then that's not just an ABS problem, that's something they need to recall. No matter why brakes are releasing, whether it's cause by the ABS computer or something else, it needs to get fixed if it's happening.

 

I had it serviced after the rock crawling incident and the snow-sliding incidents described by others. The dealership could find no problems. I asked them to check out my 2014. Again, they found no problems, which may be correct as I have not experienced any problems yet. I haven't been in the snow this year and I locked my rear differential (disabling ABS) on my September off-road trip.

 

I meant it should be recalled and fixed. Not just looked over by a dealer.

 

AMEN!

 

I have been doing some extensive research and thinking on the Tacoma ABS system. I have also done more research on the firmware and how it operates. That thinking has come up with some VERY interesting and important thoughts. Now I am not about to go into searching every post in this thread, but I am sure I can get a lot of feedback to help out here from those who have had an issue.

Here is the school of thought:

1. The ABS system is calibrated for factory sized tires/wheels.
2. The ABS sensors are measuring wheel speed at the hub itself.
3. When the truck is physically moving forward at say 45MPH, the ABS sensor also says 45MPH
4. With oversized tires of say 33 inches tall, the truck would be physically moving forward at 45 MPH, but the ABS sensors would be reading approximately 13% slower (the larger the tire, the slower the hub spins over the same distance. 13% is the approx difference between a stock tire and a 33 inch tire)
5. So as you are braking, the change in rotational speed from what the ABS computer PERCEIVES is the speed, versus what the ACTUAL change in speed, COULD trigger the ABS computer into thinking that the wheels were about to lock up.

Again, this isn't an excuse for all of this, but it is just a bit of thought I have been considering. Part of this thought is also derived from when I was working at GM. When a customer had a Silverado truck and they installed larger tires, GM had a way to compensate for the change in tire size. The technician would use the scan tool to go into the computer and tell the computer what size tires were on the truck. Interestingly enough the computer that this information was entered into was the ABS computer. The service manual also states "Incorrectly entering the tire size may cause erratic operation of the ABS system."


Thoughts?

 

Do the same ABS tire size parameters exist when using a scan tool with the Tacoma ?

 

The poll I put together seemed to rule tire size out as ABS issues were reported almost equally across vehicles with stock size tires and over sized tires. I thought I was on to something too.. I still think it might have something to do with it.

 

Also, most of the people who have had this issue, including myself, don't have it all the time. It's happened to me only a couple times over three winters, and I'm not even able to reproduce it at all on a 100% stock truck.

If the issue was really related to larger tires and not recalibrating the system, then it would happen all the time and would be much easier to replicate. Same thing if bad tires were the main cause too.

 

ABS should not be concerned with an absolute value of speed, rather the relative change in speed from rotating to zero as compared to other wheels.