Vehicle Speed Sensor: Testing and Inspection

Diagnostic Procedures

Speed Signal, Checking

Special tools, testers and auxiliary items required

• Multimeter (VAG1526) or Multimeter (VAG1715)

• Connector test kit (VAG1594)

• Wiring diagram

Test requirements

• Fuses in E-box (plenum chamber, left) must be OK:





• Motronic Engine Control Module (ECM) Power Supply Relay (J271) must be OK, check:

• Motronic Engine Control Module (ECM) Power Supply Relay 2 (J670) must be OK, check:

• Control module with indicator unit in instrument panel insert (J285) must be OK.

• Battery voltage must be at least 11.5 volts.

Function test

• To check the speed signal, vehicle must be driven at a speed above 5 km/h.

Observe safety precautions that apply to road tests.

- Connect diagnostic tester.

- Start engine and let run at idle.

- Under address word 33, select "Diagnostic mode 1: Checking measured values."

- Select the measuring value "PID 13: Vehicle speed".

- Perform a road test at a speed above 5 km/h while a 2nd person observes the indication on the display.

- Check specified value of the vehicle speed:





• Vehicle speed must not drop to below 5 km/h during test.

- End road test and switch ignition off.

If no speed is indicated:

- Check wires according to wiring diagram.

Checking wiring

- Connect test box to control module wiring harness , connect test box for wiring test.

- Remove instrument cluster.

- Check wire connection from Engine Control Module (ECM) to Control module with indicator unit in instrument panel insert (J285) according to wiring diagram:

Final Procedures

After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to --> [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.

2. If necessary, erase the DTC memory. Refer to --> [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

3. If the DTC memory was erased, generate readiness code. Refer to --> [ Readiness Code ] Readiness Code.