Newer vehicles have an electronic stability control system. This is a computerized system which is responsible for regulating the stability of the vehicle. It does this by communicating with various sensors throughout the vehicle which detect its traction and speed. If the tires were to skid or control of the vehicle were lost, the sensors would work with the electronic stability control system to help the driver regain stability through the steering wheel.
One of these sensors is called the steering angle sensor. This sensor is responsible for measuring the position of the steering wheel in terms of its rate of rotation and angle. The steering angle sensor is positioned within the steering column’s sensor cluster. In most vehicles, there are multiple steering angle sensors which each make their own calculations to ensure the data is accurate. The electronic stability control system module is sent two different signals for position verification of the steering wheel.
The two main types of steering angle sensors are analog sensors and digital sensors. We’ll go over the differences for you now.
Analog sensors are the original steering angle sensors. They look at the voltage differences to calculate the rate of turn and angle of the steering wheel’s position. To get more specific, a signal is produced by the steering angle sensor each time the steering wheel is rotated. When the wheel is in the starting position and then gets completely rotated 360 degrees, it goes from 0 volts to 5 volts. If the wheel is turned right, the positive voltage is produced. If the wheel is turned left, then a negative voltage is produced. There are no computers used here to calculate the data. The analog sensors just know when instability exists based on the voltage differences produced.
Digital sensors measure the position of the steering wheel’s angle and rate of turn by using a tiny LED light. When the light is interrupted, it is measured by an optic sensor. From there, a digital square wave signal is produced by the sensors. The frequency of the signal is dependent on how fast the driver turns the steering wheel. The more turning that is done, the more the voltage increases as the wheel is rotated farther from the center. But when the wheel is kept straight, there is a lower voltage. All the calculations of this data are sent to the computer. If the computer sees an inconsistency in relation to the direction the vehicle is moving and the position of the steering wheel, then a stability action is activated to give the driver more control of their driving.
For instance, if the driver understeers when trying to make a turn, the inner rear brake is automatically activated to compensate for this. If the driver oversteers, then the outer rear brake is automatically applied. Either of these actions is meant to give the vehicle more stability as it moves in the desired direction. Whenever there is a problem with a steering angle sensor in newer vehicles, there is a warning light that activates which lets you know there is a problem with the stability system. From there, you can have the system check out by a mechanic to verify if the steering angle sensor is to blame.
If you ever get repairs done or components replaced in your steering system, then you’ll need to recalibrate the steering angle sensors appropriately. You may be able to do a self-calibration in certain newer vehicles. This is where you just turn the steering wheel all the way from the left to all the way to the right, and then centered again. Otherwise, you’ll need a scanning tool to do an angle sensor reset. If you don’t know how to do this, go to the mechanic and let them do it for you.