Just to be clear up front, I like Toyota, they build a good car. Kinda boring for the most part, but under the hood, they make one of the most reliable drive assemblies I have ever seen.
Here is a link to a story, but it’s blah blah. The thing to look at is the photo. If this is the actual problem, it makes sense. It looks like the gears tend to wedge themselves together and stick. The fix looks decent, but it’s too early to tell. In my opinion, the proper fix is to replace this design with an older one that doesn’t use gears. In reality, this would cost millions of dollars to do, as there are over a million cars with the problem.
However, there is an even more simple solution that can be done in software. Volkswagen has, built into the software in the control module, instructions to ignore the gas pedal signal if the brake pedal is pushed for a number of seconds. this can be done through Toyota with a software update.
I can tell you that this is not an electrical problem. Almost all cars are “drive by wire” now. So are some newer jumbo jets. This means there is no mechanical function from the gas pedal to the engine. The sensor is actually 3 separate resistors that the computer looks at. The position of that sensor is seen by the computer, and the appropriate position is actuated by a stepper on the throttle assembly on the engine. If there is a problem with any one of them, the check engine light will come on, and the car goes into “limp mode”. The throttle automatically returns to a ‘just above idle’ position (its designed natural rest state). Same thing if the throttle body itself sticks, and your foot is not on the pedal at all. In this Toyota situation, the computer has no idea that your foot isn’t there, it just sees that the pedal is down.
In any fly by wire car, the proper thing to do is put the car in neutral and step on the brake to stop, then call a tow truck. The engine will sound scary as it revs up, but there are controls that keep that revving from destroying itself. similar to how the RPM in a race car is limited.
I do not recommend this, but my own response is to turn off the ignition. When you do this, you lose all the power assist that the engine provides making it harder to stop and steer. However, many newer cars have a push button instead of a key. To shut the engine off in an emergency, hold the start button for 3 seconds.
The very idea of putting yourself in a metal box that turns small explosions into bone crushing speeds is a risk. What I’m tired of hearing about is that its all Toyota’s fault. No, its the drivers fault, driving is a risk. Anyone killed in a car took the risk to get in it in the first place. Many innovations reduce that risk, but none eliminate it. If anything goes wrong in a car, its panic and stupidity that will kill you faster. Think. Get to know your car. Learn how it works, learn how to drive it, how to stop it, and what breaks it. Stop treating it like an inconvenience you tolerate. Oh, and RTFM!
Posted on February 4th, 2010 by Geekwrench
Filed under: Uncategorized