Connect GDS with 'DATA LINK CONNECTOR' (DLC).

Warm engine up to normal operating temperature.

Turn all the electrical devices including air conditioner OFF.

Monitor VEHICLE SPEED SENSOR" parameter on the GDS.

Fig.1) Check if actual vehicle speed is equal to measured vehicle speed by GDS.

☞ If invalid VSS data is detected, Check if there's malfunction relative to ABS/ESP wheel speed sensor.