Brake Override System

[Jtraskell]

I have seen this mentioned in various threads regrading brake funtions and sounds etc.etc. In at least one thread, a couple of folks stated they tested thier new T4R and thought they had the system. However, the test(s) were described as traveling at a certain speed, then hitting the brake and the gas at the same time. One person said thier RPM's were at 2400 or so when the vehicle stopped or something to that effect. I do not think one is going to determine if you have the override progaming while doing that type of test. At best, you are verifying you have good brakes!

The override system will not allow the motor to go past 1500 to 1800 RPMs when the brakes and gas are pressed at the same time. In other words, you should NOT be able to power brake you vehicle.

Try this. At a standing still point, 0 mph, place your foot on both the brake and the gas. Hold the brake firmly, then apply the gas "slowly increasing". If your engine goes above 2k rpms or if your rear tires start to brake loose, (power braking), you probably do not have the system. The gas is still the primary input to the computer and it is not being overridden by the brake function.

I tested mine the other day, built 12/09, Rpm's hit 3K then the rear tires started to break loose. I do not have the system. Some of you others might have the system if yours were built at a later date or, maybe it came with the limited at first, then others later who knows.

 

[offshorebear]

Don't balloon your torque converter by doing that too often.

I'm surprised to hear that at a stop the rear wheels broke loose against the brakes. Did the car move forward at all?

I think it should be programed to cut the gas if you are at high RPM, say >4k. Left foot braking is very useful off road so there is a need to have the ability at lower RPM.

 

[Jtraskell]

Don't balloon your torque converter by doing that too often.

I'm surprised to hear that at a stop the rear wheels broke loose against the brakes. Did the car move forward at all?

I think it should be programed to cut the gas if you are at high RPM, say >4k. Left foot braking is very useful off road so there is a need to have the ability at lower RPM.

No once was enough! Since this is a safety feature, as it was explained to me, it was the preassure of the brake, overridding the pressure of the gas. Now, light braking, while still applying gas should not kick the override in. Or, maybe becuase of the off roading stuff we are expected to do, it will never be incorporated in the T4R. But an accelration override should occur at any speed when the brakes are applied hard enough, shutting down the RPMs to the engine to very little. Speed should not matter. But hey, been wrong before!

 

[Jed]

Keep in mind that some vehicles also have a rev limiter when the vehicle is in Park or Neutral. I have no idea if the 5th gen 4Runner has it or not, but I have been in vehicles that will not allow the engine to rev past approximately 3000 RPM when in Park or Neutral.

 

[T4Fun]

I have seen this mentioned in various threads regrading brake funtions and sounds etc.etc. In at least one thread, a couple of folks stated they tested thier new T4R and thought they had the system. However, the test(s) were described as traveling at a certain speed, then hitting the brake and the gas at the same time. One person said thier RPM's were at 2400 or so when the vehicle stopped or something to that effect. I do not think one is going to determine if you have the override progaming while doing that type of test. At best, you are verifying you have good brakes!

The override system will not allow the motor to go past 1500 to 1800 RPMs when the brakes and gas are pressed at the same time. In other words, you should NOT be able to power brake you vehicle.

Try this. At a standing still point, 0 mph, place your foot on both the brake and the gas. Hold the brake firmly, then apply the gas "slowly increasing". If your engine goes above 2k rpms or if your rear tires start to brake loose, (power braking), you probably do not have the system. The gas is still the primary input to the computer and it is not being overridden by the brake function.

I tested mine the other day, built 12/09, Rpm's hit 3K then the rear tires started to break loose. I do not have the system. Some of you others might have the system if yours were built at a later date or, maybe it came with the limited at first, then others later who knows.

what is official test for this function? personally i am very suspicious why toyota included this on the 4r, not that I complaining about the feature in general. I think the engine should not rev no matter what if both brake and accelerator are pressed.

 

[Uneek]

Jtraskell,

:iagree: Your assessment is how I interpretted the brake override should work based on testing done on other manufacturers' vehicles that have the system. If the engine revs and allowing the vehicle to brake free, how is that any different.

what is official test for this function? personally i am very suspicious why toyota included this on the 4r, not that I complaining about the feature in general. I think the engine should not rev no matter what if both brake and accelerator are pressed.

I don't know about the '10 4Runners. In the hearings, Jim Lentz said that all but one or two '11 Toyota models will have the brake override.

Come to think of it, I guess with the brake override it'll be harder to drag race. No, I don't specifically mean a SUV like the 4Runner, but cars or those where accleration times mattered, etc.

 

[charlier180]

Jtraskell,

:iagree: Your assessment is how I interpretted the brake override should work based on testing done on other manufacturers' vehicles that have the system. If the engine revs and allowing the vehicle to brake free, how is that any different.



I don't know about the '10 4Runners. In the hearings, Jim Lentz said that all but one or two '11 Toyota models will have the brake override.

Come to think of it, I guess with the brake override it'll be harder to drag race. No, I don't specifically mean a SUV like the 4Runner, but cars or those where accleration times mattered, etc.

I have a friend who is a technician who works at the dealership of a German automaker. A while back he had a customer who complained that his car hesitated badly. He went out for a test drive with the customer. During the drive he noticed that the customer drove with two feet. One on the brake and one on the gas (at the same time). When pulling out of the dealership lot there was a pronounced hesitation. After a while he asked the customer to pull over. He then proceeded to explain how driving with two feet was not a good idea in this and all the models the automaker sold because every model had brake override software built into their drive by wire system. Then my friend switched positions with the owner, drove with one foot on either the gas or brake and magically the hesitation disappeared.

Last my friend heard the customer learned to drive with one foot and was very happy with their vehicle. Given everything in the news about many Toyota models lacking a brake override in their drive by wire systems, this German car owner is probably even more happy knowing that the German automaker chose to incorporate this feature in their models over 10 years ago.

I as a Toyota owner would really like to know the reasoning/logic behind Toyota's decision NOT to include brake override software in their drive by wire systems.
Unfortunately, I get the feeling that we may never find that out unless it comes out in one of the cout cases that are sure to take place sometime in the future.

 

[Jed]

I

I as a Toyota owner would really like to know the reasoning/logic behind Toyota's decision NOT to include brake override software in their drive by wire systems.
.

Drive-by-wire is relatively new....it wasn't that long ago that most vehicles have cable-actuated throttle linkages. Some manufacturers obviously felt that brake override wasn't necessary, but I think that's changing quickly. Our '09 Acura doesn't have it either and I'm not really surprised.