Speed Signal, Checking

Speed Signal, Checking

Recommended Special Tools, Workshop Equipment, Testers, Measuring Instruments and Auxiliary Items
- V.A.G 1526 portable multimeter or V.A.G 1715 multimeter
- Adapter set V.A.G 1594
- Wiring diagram

Test Conditions
- The respective fuses of Motronic Engine Control Module (ECM) -J220- must be OK:
- Battery voltage must be at least 11.5 V.
- Speedometer -G21- must be OK.

Test Sequence

NOTE: To test the speed signals, the vehicle must be driven. This requires a second person.

CAUTION: Secure Scan Tool (ST) on the rear seat and operate it from there by second technician.

- Connect diagnostic tester. Diagnostic Tester, Connecting
- Start engine and let run at idle.
- Under address word 33, select "Diagnostic mode 1: Checking measuring values."
- Select the measuring value "PID 13: Vehicle speed".
- Perform a road test, and have a second person observe the indication on the display.
- Check specified value of the vehicle speed:







- End diagnosis and switch ignition off.

If no speed is displayed:
- Connect test box to control module wiring harness. Test Box, Connecting For Wiring Test
- To measure voltage, connect multimeter between sockets 3 (terminal 15) +54 (speed signal) of test box.
- Raise vehicle at left front.
- Switch ignition on.
- Turn front wheel and observe voltage display when doing so.

Specified value: 0.0 to at least 4.0 V, fluctuating

NOTE: Right front wheel must not turn, secure if necessary.

If display does not fluctuate:
- Remove instrument cluster
- Check wire connection from Engine Control Module (ECM) to Speedometer -G21- according to wiring diagram.
- Erase DTC memory of ECM. Diagnostic Mode 04 - Erase DTC Memory
- Generate readiness code. Generate Readiness Code