Automobile & Light Truck Certification Test A5 BrakesAnti-lock Brake System (ABS) Diagnosis and RepairMedium
A vehicle with Electronic Stability Control (ESC) activates the system during a sudden evasive maneuver. Which of the following components is PRIMARILY responsible for detecting the vehicle's rotational movement around its vertical axis?
- AWheel Speed Sensors
- BLateral Accelerometer
- CSteering Angle Sensor
- DYaw Rate Sensor
Show answer & explanationAnswer & explanation
Correct answer: D. Yaw Rate Sensor
The yaw rate sensor specifically measures the angular velocity of the vehicle around its vertical axis, which is crucial for detecting oversteer or understeer conditions that the ESC system needs to correct. This rotational movement is key to stability control.
Why the other options are wrong
- A. Wheel speed sensors primarily detect individual wheel speeds, which are used to calculate vehicle speed and detect wheel slip, but not directly rotational movement around the vertical axis.
- B. A lateral accelerometer measures side-to-side acceleration (G-forces), which helps determine cornering forces, but doesn't directly measure the rate of rotation.
- C. The steering angle sensor measures the driver's steering input, indicating the intended direction, but not the actual rotational motion of the vehicle.
Yaw Rate Sensor
A sensor that measures the rotational velocity of a vehicle around its vertical axis (yaw). This input is vital for Electronic Stability Control (ESC) systems to detect and correct oversteer or understeer.
- Measures degrees per second of rotation.
- Often integrated with the lateral accelerometer.
- Critical for ESC system operation.
Memory trick: ESC's Eye: Yaw, Steer, Speed, G-Force, Brake!