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 set
- Wiring diagram

Test requirements





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

Test sequence

NOTE: To test speed signal, vehicle must be driven. Doing this requires a second person.

WARNING: Secure Scan Tool (ST) on the rear seat and have operated 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 the 2nd person observe the indication on the display.
- Check specified value of the vehicle speed:






- End diagnosis and switch ignition off.

If no speed is indicated:
- Connect test box to control module wiring harness, connect test box for wiring test. Test Box, Connecting For Wiring Test

Vehicles with engine code AHA
- Connect multimeter between sockets 2 + 20 (speed signal) of test box for voltage measurement.

Vehicles with engine code ATQ
- To measure voltage, connect multimeter between sockets 3 (terminal 15) + 54 (speed signal) of test box.

Continuation for all vehicles
- Jack up front left wheel.
- Switch ignition on.
- Rotate front wheel, and observe voltage indicated while doing so.
Specified value: 0.0 to at least 4.0 V, fluctuating

NOTE: The right front wheel must not turn during this, hold it steady if necessary.

If indicated voltage does not oscillate:
- Remove instrument cluster:
- Check wire connection from Engine Control Module (ECM) to Speedometer -G21- according to wiring diagram.
- Erase DTC memory of Engine Control Module(ECM), Diagnostic mode 4: Reset/erase diagnostic data.
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes