ShrinkDoc

Noticed that in the last month the brake override system failure light came on twice and the car dropped speed (60mph to 5mph) within seconds. Anyone have experience with this phenomenon? What have you learned.

Sasnuke

Did the message say there was a malfunction and to take it to the Dealer?
Your description of the speed dropping sounds like the system was activated, rather than malfunctioning.

If it did give you a malfunction warning, then checking some basics like the battery or any aftermarket electrical accessories would be a good place to start.

arentz07

Note, the malfunction could have been the activation itself.

ShrinkDoc

Really good point--THANK YOU! It's just a light that comes on for 3-5 seconds, then goes off. Thoughts?

ShrinkDoc

Can you expand on this? What does this mean? I think I understand, but want to be sure.

arentz07

The error was that the braking was applied at all, when it should not have been. I was just nitpicking Sasnuke's post.

Sasnuke

If it was just the system activating, this is caused by the accelerator being depressed, and then the brake being depressed...so both pedals are depressed, in that order.
The ECM interprets this as the driver attempting to slow a vehicle that is uncontrollably accelerating, so it returns the throttle body flap to the idle position, therefore allowing the brakes to bring the vehicle to a stop.

You can simulate this by driving down the road...where it's safe (can't stress that enough), and while you are still pushing the accelerator, use the other foot and press the brake.
You have to be at some significant speed for the override to kick in.

So why would this activate if you weren't doing the above steps? Most common cause is big shoes/feet hitting both pedals without you realizing.

HOMER350

Sounds dangerous.
Still too often I see someone dual-footing the gas/break pedals.

ShrinkDoc

Problem solved... The rubber mat was sitting on the edge of the break and pressing the brake as the gas pedal was pressed. How stupid can I get?

HOMER350

Eh, at least you discovered it before a worse incident.

ShrinkDoc

yeah...or before I spent 100's at the dealership or a shop.

Sasnuke

Is it a Lexus mat or aftermarket?

I should have suggested that it may have been the mat too, since about 10 years ago this was a hot topic for Toyota when people used aftermarket mats, especially in the winter.
They resolved that issue in 2012 by selling all vehicles with carpet and all weather mats...which can both be secured to the tabs in the footwell floor, therefore never interfering with the pedals.
Of course this is in Canada, so I'm not sure if they did this in a ll regions...especially if you don't have traditional winter.

Flash5

Almost all cars in the states have the tabs to secure down the mats.

Sasnuke

Let me clarify what I was trying to say...as the cars were only shipped with the carpet mats, people would just buying cheap aftermarket mats for winter that did not have the holes to use the locking tabs with.
Eventually the mats would ride up and get caught in the pedals...hence creating the problem.
So in 2012 Toyota provided, along with the traditional carpet mats, a set of the all weather mats that you would have traditionally had to purchase for an additional cost from the dealer.
Effectively cars were coming with 2 sets of mats...carpet and the rubberized all weather.
Once owners were swapping between the mats each season, and using the locking tabs each time, there shouldn't have been any further mat issues.

BlazeL

At your 5k and 10k services at Lexus one of the checkpoints for the visit is to actually ensure the mat is properly fitted as it should be. I assumed it was for the accelerator pedal but I guess it could be for the brake as well. Especially if your ShrinkDoc