Cars · Diagnostics
OBD0 Vehicle Speed Sensor (VSS) Data Reference
Technical reference for the OBD0 Vehicle Speed Sensor (VSS) data, including RAM memory location, linearity, and conversion formulas.
The Vehicle Speed Sensor (VSS) data in OBD0 ECU systems is stored in RAM location 06Ch.
Technical Specifications
The VSS signal is linear; however, the system has a maximum readable threshold of approximately 157 kph.
Data Conversion
To convert the raw hexadecimal or decimal value from RAM location 06Ch to kilometers per hour (kph), use the following linear approximation:
Formula:
Speed (kph) = 0.6229x - 2.1385
Note
The variable x represents the decimal value retrieved from RAM address
06Ch.
Important
The sensor data saturates at approximately 157 kph. Values exceeding this threshold will not be accurately represented by the ECU.