Vehicle Speed Sensor (VSS) — Replacement (Chevrolet Trailblazer 1)

1. The vehicle speed sensor (VSS) is a generator of a constant magnetic field. It is located on the gearbox. When the toothed rotor located on the secondary shaft of the gearbox rotates, the sensor is exposed to an alternating magnetic field.

Thus, when the secondary shaft of the gearbox rotates, the sensor generates an alternating pulse, the frequency of which is directly proportional to the speed of the vehicle. The sensor pulses are the initial ones when determining the engine and gearbox control parameters in the PCM. Also, when processing this pulse, the radio receiver is adjusted. The signals from the VSS sensor are used to control the speedometer drive located in the instrument cluster. Failure of the sensor may lead to problems with the engine and transmission.

Replacement

2. Raise the vehicle and support it on vertical stands.

3. Disconnect the VSS sensor connector (see illustration).



4. Unscrew the bolt and remove the sensor from the gearbox housing.

5. Replace the sensor O-ring and lubricate it with clean engine oil.

6. Installation is carried out in the reverse order of removal.