Speedo Sensor Drives and Gears

SPEEDO DRIVE SENSORS AND GEARS

Types of Speedometer Sensors:

There are typically two types of speedometer sensors in modern vehicles:

  1. Magnetic Pickup (VSS - Vehicle Speed Sensor):
    • Function: These sensors use a magnetic field to detect the movement of a metal object (often a toothed wheel or gear) that rotates as the vehicle moves. The sensor sends electrical pulses to the vehicle's ECU, and the frequency of these pulses correlates to the speed of the vehicle.
    • Location: Magnetic pickup sensors are often located on the vehicle's wheel hubs, transaxle, or driveshaft.
  2. Hall Effect Sensor:
    • Function: Hall Effect sensors detect the presence of a magnetic field as the vehicle's rotating components (like a toothed wheel or gear) pass in proximity to the sensor. These sensors generate a digital signal corresponding to the wheel's speed.
    • Location: These sensors are often mounted on the vehicle's transmission or differential and are connected to the ECU.

How It Works:

  • Detection of Rotation: The speedo sensor typically works by detecting the rotation of a gear or magnet attached to a rotating part, like the wheel, axle, or driveshaft. As the vehicle moves, the component turns, and the sensor picks up the motion, converting it into an electrical signal.

  • Signal Transmission: The sensor sends a signal to the vehicle’s instrument cluster (analog or digital speedometer) or ECU. This signal is then processed to calculate the vehicle's speed, and the result is displayed on the dashboard.

  • Calculation: The speed is usually calculated based on the number of pulses the sensor generates per unit of time. The more pulses per second, the higher the vehicle's speed.