Seville V8-273 4.5L (1989)
Vehicle Speed Sensor: Description and Operation
Vehicle Speed Sensor
The Vehicle Speed Sensor (VSS) is a pulse generator which is mounted in the transaxle. A toothed reluctance ring rotates near a magnetic pickup,
producing a voltage signal that is proportional to the vehicle speed. The speed sensor produces a weak signal. A vehicle speed sensor buffer amplifier is
placed between the speed sensor and the Electronic Control Module (ECM) to amplify the speed signal. The buffer amplifier decodes the signal from
the speed sensor to a digital signal, and sends it to the ECM. The ECM uses this signal for the logic required to operate the fuel economy data panel, the
integral cruise control, the idle speed control system, Viscous Converter Clutch (VCC), and to modify fuel delivery under certain vehicle conditions. A
speed sensor or circuit which is not functioning properly will set a code E024.
