Genuine OEM Audi Wheel Speed Sensor Rotor, part number 1J0614149. This toothed metal ring is crucial for providing accurate rotational speed data to the wheel speed sensor, which is vital for the anti-lock braking system (ABS) and traction control. It is typically installed on the rear axle. This rotor measures approximately 78mm in diameter. Choosing genuine OEM ensures the precise tooth count and material integrity required for accurate sensor readings and reliable operation of critical safety systems.