Vehicle Speed Sensor: Description and Operation

The Vehicle Speed Sensor, located in the speedometer assembly, is an "ON/OFF" switch operated by speedometer cable rotation. The switch cycles four times per cable revolution. The ECU monitors this signal and calculates vehicle speed based on the frequency of "ON/OFF" cycles.

Vehicle speed information is utilized in ECU calculations for various outputs, including automatic transmission control. Rather than use a separate EC-AT control unit, this vehicle incorporates electronic transmission controls within the main ECU.