Vehicle Speed Sensor: Testing and Inspection

Diagnostic Procedures



Speed Signal, Checking

Special tools, testers and auxiliary items required

• Hand multimeter (V.A.G 1526) or Multimeter (V.A.G 1715)

• Test adapter kit (V.A.G 1594)

• Wiring diagram

Test Conditions

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

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

• Instrument Cluster Control Module (J285) must be OK.

• Battery voltage (both batteries) must be at least 11.5 Volts.

• The fuses must be OK:

Right instrument panel fuse holder





Test Sequence

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, refer to Repair Manual.

- Connect diagnostic tester.

- Start engine and let run at idle.

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

- Select measured value "PID 13: Vehicle speed".

- Perform a road test at a speed above 5 km/h and have a second person observe 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 displayed:

- Check Data-Bus wiring according to wiring diagram.

Checking wiring

- Connect test box to wiring harness on corresponding Engine Control Module at connecting test box for wiring test, refer to Repair Manual,

- Remove instrument cluster, refer to Repair Manual

- Repair malfunction in CAN-Bus wires between both Engine Control Modules and (J285)Instrument Cluster Control Module (J285) according to wiring diagram:

- Erase DTC memory of Engine Control Module => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09, Diagnostic mode 4: Reset/erase diagnostic data.

- Generate readiness code => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.