Vehicle Speed Sensor: Testing and Inspection
Vehicle Speed Sensor Schematic:
DESCRIPTION
The Vehicle Speed Sensor (VSS) is a variable reluctance sensor that generates a waveform with a frequency that is proportional to vehicle speed. When the vehicle is moving slowly, the sensor produces a low frequency signal. As the vehicle speed increases, the sensor produces a higher frequency signal. The Powertrain Control Module (PCM) uses this signal to control fuel injection, ignition timing and transmission/transaxle shift points. This Pinpoint Test is intended to diagnose only the following:
- VSS Harness Circuits
- Vehicle Speed Sensor
- PCM
Test DP1 - Continuous Code 29/452: Complete VSS Drive Cycle
Test DP2,3 and 4