Speed Signal, Checking

Speed Signal, Checking

Recommended special tools and equipment
- V.A.G 1526 multimeter or V.A.G 1715 multimeter
- V.A.G 1594 connector test kit
- Wiring diagram

Test requirements







- Fuses in E-box (plenum chamber, left) must be OK
- Motronic Engine Control Module (ECM) Power Supply Relay -J271- -position A3- must be OK, check
- Motronic Engine Control Module (ECM) Power Supply Relay 2 -J670- -position A1- 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

NOTE: 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:







NOTE: 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. Test Box, Connecting 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
- Erase DTC memory of Engine Control Module (ECM), Diagnostic mode 4: Reset/erase diagnostic data. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Readiness Code