Toyota 4Runner Sudden Unintended Acceleration

smsgtretired

On May 5, 2010 our 2008 4Runner exhibited sudden unintended acceleration (SUA). Wife was at a stop, foot on brake, transmission in drive when the engine went wide open and the vehicle was out of control for about 800 feet. Toyota has it and is checking it out. I have been skeptical about these claims until it happened to us. This vehicle is not on their recall but may be very soon. Will post again when Toyota has run their tests.

actualsize

When you say "Toyota has it", do you mean the dealer or some higher-level Toyota field representative? Curious to know what they say. In what city and state did this occur? I recently had an episode in a Ford Fusion Hybrid that lasted 3 seconds, but it turned out to be interference with an all-weather floor mat that was out of position.

smsgtretired

The local Toyota dealer in Taylorsville, IN has the vehicle. It is my understanding that a Toyota Field Rep will eventually evaluate the vehicle as well. So far, the Dealer tells me they have been unable to duplicate the condition and their computer tests are not showing any fault codes. This was definitely not a floormat problem. Wife's foot was on the brake and the vehicle was stopped when problem began. She rode the brake until vehicle returned to normal some 800 feet later. I have received several inquiries from private firms and have been advised that computer tests never confirm this problem. Toyota service manager pretty much implied the same thing. Until somebody figures out what is causing this and how to detect it after it occurs, the denial will continue. This is our second 4Runner. Until this incident, we were very pleased with them. Whatever Toyota finds or does not find, we cannot be comfortable driving this vehicle again. Soon as we get it back it will be traded for another brand that has a lower risk history of this. From my research all the newer vehicles have had sudden acceleration incidents. Why can't we just go back to mechanical throttles?????? Somebody will figure this out eventually! Would be nice if Toyota would cover the loss I will incur when I trade, but I am sure they won't and they are too big for me to fight with over a few thousand dollars. My wife was not hurt and nothing was damaged, so I am at least thankful for that much good fortune.

actualsize

There is no going back to cable throttles. They have many more potential failure mechanisms, and they cannot self diagnose and go to limp-home mode in any way, shape, or form. Reduced emissions, reduced fuel consumption, improved driveability, improved starting, reduced interior noise and vibration, the ability to have safety devices like traction control and stability control -- there are many more advantages to an electronic throttle system than disadvantages, including overall safety.

And the addition of a brake override system, the very system that would have made your wife's situation very easy to get out of, requires an electronic throttle to be present in the first place.

I hope they get to the bottom of your problem, but the electronic throttle is sound from an overall standpoint.

Dan

smsgtretired

The dust has all settled. Toyota says they could not duplicate the condition and could not find anything wrong. Withing 5 hours after they gave the Toyota back to me, it was replaced by a new vehicle that has a more favorable history with this problem. It is interesting that I am reading elsewhere that Toyota and others are coming out in 2012 with throttle override systems. Just precautionary I am sure: to find a cure for a disease that does not exist.

I wish they had found something wrong with this vehicle to fix and cure the event experienced. Only good thing I have to report is no financial loss. The 4runner held its value so well that I saw no loss on the trade to a new vehicle.

Once your vehicle stampedes, you will never feel comfortable driving it again. As is evident, I have no brand loyalty. Sell me a product that does not work right and I dump it for good. No second chances with me. Been through GM, Ford, and now Toyota.

wwest

'''.....brake override....requires an electronic throttle...."

No.

An independent, failsafe, brake override would simply open a circuit, spark, fuel pump, fuel injectors, if the brakes are applied and the engine doesn't quickly drop to idle.

Using the electronic throttle control, engine/transaxle control ECU, for override would be inappropriate since that is most likely to be the faulty component. And a retrofit, backfit, using the current engine control ECU, reprogramming, is reasonable approach for the EXISTING fleet. But for future systems it would be rather foolish to rely on the very same ECU firmware that may well be the causative factor. Best to use a completely independent brake override system/path.

wwest

I wonder if some of these problems, SUA problems, might be the result of an intermittent, possibly one time failure, of the brake power boost system, engine VACUUM boost. If the vacuum boost valve shut remains open when you apply the brakes that would provide a serious level of airflow into the engine manifold, the upstream oxygen sensor would detect an oxygen rich environment and enrich the mixture accordingly.

Not full throttle but a rather serious level of engine PULL....

tsu670

I understand Toyota has been adding the brake override feature to all of the vehicles they have been repairing under the recall. It's too late now (sounds like you already traded it for something else), but how hard would it have been for them to add the override to your 4Runner?

wwest

The only way to easily and quickly retrofit, backfit, a brake override is to reprogram the firmware for the engine/transaxle controlling ECU, firmware that itsself might well be the SUA causative factor.

Good luck on that...!!

tsu670

Toyota has been retrofitting the brake override feature on thousands of vehicles in the past year.

If this is something I decide to do (or not do) with my 4Runner, it will be because I received more authoritative information on the matter than what I might get from a Car Space forum.

bobbyrlove

I own a 2008 Toyota 4Runner SR5 V6 2 wheel drive with 70230 miles. Never a single problem until the past 2 weeks. Twice I have noticed when stopping at a stop light just before the car was completely stopped the car would try to accelerate. Both times I had my foot firmly on the brake and had to press much harder to stop the car from moving forward. Both times it only lasted for a second or two but I am beginning to not trust the car. I would not consider letting my wife drive this car.