Vehicle Speed Signal, Checking

If the vehicle speed signal is faulty, first determine whether the signal reaches the speedometer.
- Connect VAG1551 or VAG1552 scan tool.
- Read measuring value block.
- Select channel number 001 and road test vehicle.

If the vehicle speed is shown in the display of the scan tool, the instrument cluster is faulty and must be replaced.

If the scan tool does not show the vehicle speed in the display, check the multi-pin connector at the instrument cluster.

- Remove instrument cluster.
- Connect VAG1598 test box with VAG1598/4 adapter to red 26-pin connector.
- Using Fluke 83 multimeter, measure voltage between socket 24 and vehicle ground.
- Move vehicle a little forward and backward.
Specified values: voltage must increase from 0 V to approx. 12 V and then decrease to 0 V (pulsating direct voltage)
- If not, check wiring to vehicle speed sensor.
- If the wiring is OK, replace vehicle speed sensor.