Lanos S Hatchback L4-1.6L DOHC D-TEC MFI (1999)
Vehicle Speed Sensor (VSS): Description and Operation
AUTOMATIC TRANSMISSION VEHICLE SPEED SENSOR (A/T VSS)
The Automatic Transmission Vehicle Speed Sensor (A/T VSS) is a magnetic inductive pickup that relays information relative to vehicle speed to the
Powertrain Control Module (PCM). Vehicle speed information is used by the PCM to control shift timing, line pressure, and Torque Converter Clutch
(TCC) apply and release.
The Vehicle Speed Sensor (VSS) mounts in the case at the speed sensor rotor which is pressed onto the differential. An air gap of 0.27 - 1.57 mm
(0.011 - 0.062 inch) is maintained between the sensor and the teeth on the speed sensor rotor. The sensor consists of a permanent magnet surrounded
by a coil of wire. As the differential rotates, an AC signal is induced in the VSS. Higher vehicle speeds induce a higher frequency and voltage
measurement at the sensor.
Sensor resistance should measure between 1500 - 1750 ohms at 20°C (68°F). Output voltage will vary with vehicle speed from a minimum of 0.5
volts AC at 25 RPM to 200 volts at 1728 RPM.
