Throttle adaptation reset and relearn

Gentle driving can be described as conservative while harsh or aggressive driving can be described as sporty.With throttle adaptation, the vehicle is able to determine the driving style of the driver and the throttle valve position is adjusted according to the behavior of the driver. Some drivers drive conservatively while some others drive sportily.

If a driver who drives sportily drives a car of another person who drives gently, the throttle response will be slow to him since the car has adjusted to the driving behavior of the conservative driver.

 

When a car adapts to the driving behavior of a driver, either the throttle position or injection quantity or both is adjusted in relation to the accelerator pedal position. If we plot a characteristic curve of throttle position/injection quantity versus accelerator pedal position, it is going to be progressive for a conservative driving style and degressive for a sporty driving style.

For progressive, a small depression of accelerator pedal is going to cause a small opening of the throttle butterfly valve. There will be greater opening of the valve if there is more depression of the throttle pedal. For degressive, there is a steep rise in throttle opening for a small accelerator pedal angle and the throttle opening flattens out as the accelerator pedal is depressed further. This is what makes the car feels very responsive to a sporty driver.

A car can also adapt to an intermediate driving style. This characteristic curve is also a function of the speed of the vehicle snd the adaptation is continuous.

The accelerator pedal position signal is subjected to low pass filtering in some conditions. The parameters of filtering  are varied depending on driving behavior. This prevents abrupt changes in driving performance and therefore improves comfort. It occurs only during conservative driving.

 

Throttle adaptation reset

Throttle adaptation reset can be performed using a quality and appropriate scan tool. There are also different shortcut methods for different cars which involves cycling of ignition key and/or pressing of accelerator pedal.

 

Examples of throttle adaptation reset methods

Without making reference to specific cars, let's see some common throttle adaptation methods.

Example 1

1. Put key in ON in key ON, engine OFF mode

2. Press down on the gas for at least 60 seconds 

3. Turn car on and drive.

Example 2

1. Insert fob into slot (if you have a key, turn it 2 clicks to the right)

2. Press Start/Stop Engine button

3. Depress gas pedal all the way down for at least 30 seconds

4. Release gas pedal.

5. Wait about 30 seconds

6. Start car.

Example 3

1. Turn key to ACC position for 10 seconds

2. Turn key to off for 10 seconds

3. Start car.

Example 4

1. Push Engine button ON without starting the engine

2. Step on the throttle pedal down (all the way down)

3. Hold it there for 30-40 seconds.

4. With throttle still down, push Engine button OFF.

5. Release throttle.

Example 5

1. Get in your car.

2. Turn the key to the on position, the position just before the starter turns over.

3. Press the gas pedal to the floor with the key in the "ON" position.

4. Hold the pedal to the floor for five seconds, then turn the key back to the "off" position with the key still in place, then release the gas pedal.

5. Wait 2 mins. for a full alignment. During this time you may hear very faint noises and clicks. I

only heard one sitting in my car, if I got out and popped the hood I might hear more.

6. Drive.

These examples are not exhaustive and only one method will work for a car.

Some vehicles get their throttle adaptation reset when battery is removed for a substantial period of time.

When relearning of new throttle position is taking place when key is off and engine is ON, you hear the noise of the throttle body adjusting position of the butterfly valve. This process is called throttle body alignment.

Aside throttle adaptation, there is another type of adaptation which has to do with learning shift pressures and timings of automatic transmissions. They should not be confused.