Brand New Tacoma with Brake Failure

My next step is to type a letter to Toyota Corporate and explain everything. In the meantime I am not going to go rogue and attempt to induce the issue by driving around for miles and miles. It will happen again. It's just a matter of time. When it does I will contact the dealer again to cover myself and send written notification to Toyota.... again. I have not spoke to Toyota directly since the dealership gave me their bogus print out of my intentional brake testing on 7/24. I find it funny how common sense has been thrown to the way side by the dealer. So what we are saying is that after 18 years of driving, I am now using 2 feet to drive. SMH

 

You have to also see it from their point of view. They get many false claims from owners that either make mistakes or dont want their vehicle anymore. Remember the whole 'unintended acceleration' debacle that even NASA couldnt replicate? Not saying you arent having an issue, just that they will be very suspicious of such a claim.

As computers are widely used on our vehicles, these are still very mechanical machines. The brake system is a completely mechanical system with a computerized abs. Another words, the issue you are describing is mechanical over computer because of the fact that the computer couldnt physically allow the pedal to go to the floor. Its a mechanical hydraulic system, not a 'brake by wire'. In fact, if you were to remove the abs fuse, the brake system were work normally, minus the abs.

The throttle is 'throttle by wire' which is a completely computerized system. When you push your accelerator pedal a sensor tells the throttle body how much to open and the amount of fuel to deliver. This is why there was such a stink about unintended acceleration because if it was fully a mechanical system, the uninteded acceleration that was talked about would be impossible. They had to prove it wasnt occurring.

As you can see in the diagram (albeit this is a general image, it still applies) when you apply the brakes the plunger from the pedal compresses the hudraulic fluid throughout the entire system. In order for the pedal to drop to the floor there has to be a mechanical failure somewhere.

The only other reason a pedal generally drops to the floor is air in the brake lines. But with this problem you would have spongy brakes and the issue would occur every time you hit the brakes.

 

You are incorrect. There are several causes for a pedal to drop to the floor. Fluid leak; IE: caliper, hose, line, wheel cylinder, master cylinder. ABS valve could be bypassing pressure internally. Maladjusted rear drum brakes. Master cylinder internal bypassing.

 

Apparently you didnt read my post. Those are ALL mechanical failures. That is what im speaking of.

 

Welcome to TW!

 

Brakes on the 2016 are still hydraulic, but the booster, ABS, VSC, TRAC are all electronic. I think that's where this issue will be, something in one of those systems is scrambling thinking the truck is skidding. Maybe it's in the controller, pump or a wheel sensor, but I highly doubt it's a hydraulic issue since something like that is going to either fail or not and you'd think just about any mechanic could follow the leaking brake fluid.

 

OP stated the pedal went to the floor. None of those systems would allow the pedal to drop to the floor. Also stated that there was no noise. The abs and trac functions are quite noisy.

 

This is why Im trying to clarify what happened. If the pedal didnt go to the floor when applied but the truck didnt stop, then that would sound like an overactive ABS. But its quite obvious when ABS kicks in. Its noisy, the pedal pushes back up at you. All the driver nanny systems are delivered via the ABS.

 

An faulty abs valve could cause a loss of pedal either mechanically or electronically. I've seen it both ways. Won't be noise if the pump isn't running but a valve is active

 

I will say that I find the two pedals a little too close and I have pushed both unintentionally. I don't wear clown shoes, but my feet ain't small.

If the pedal just goes to the floor with almost no resistance, it could be a sticky check valve or something.... I'm not sure how this system is laid out, but I have had a leaky brake cylinder and loss of enough fluid that I had to "pump" the brakes up before they would work. Also, there could be an issue with the power brake system. I know on older GM cars, if you didn't have the vacuum line hooked up to the master cylinder brake assist, it would act the same way. I'm sure, the Taco has something similar.

 

I have the old style brake system, vacuum booster, separate ABS controller, no VSC. So I'm just throwing out dumb ideas. The ABS on my truck is definitely noisy, for sure. It has let the pedal drop pretty far to the floor if I ask it to activate back-to-back to quickly.

Doesn't the skid control ECU store information on activation? If it is electronic I'd think that system is either going to give you data or be the suspect. Otherwise diagnosing a failing master cylinder if it's piston seals are bad isn't new ground. Could there just be air in the lines? Again, that ain't rocket surgery to figure out or repair.

 

Absolutely. Low fluid/air in the line too.

 

Dealt with this on a truck last week. His problem ended up being a master cylinder leaking out the primary seal

 

Haven't seen this asked, but is the parking brake working? Honest question.

 

Who is going off topic?

 

I agree it could be some internal failure in the abs unit. I dont know on the tacoma if this would allow the pedal to drop. Again, the computer systems arent going haywire and causing brake failure. Thats the point I was trying to make. Somewhere something mecahnically isnt functioning.

 

Women you are awesome. You are turning me on

 

How can you definitively say this is not electronic? If it was mechanical then it seems like it should be straightforward to diagnose. The skid control ECU stores data on activations so shouldn't the DTC log tell you what happened or perhaps even replicate it in test mode? I guess that's why it has to be mechanical, since I assume that's been tried.

 

She's just frustrated.

 

Ahahaha!