Vehicle Speed Sensor: Testing and Inspection

Speed Signal, Checking

Recommended special tools and equipment
- VAG 1526 multimeter or VAG 1715 multimeter
- VAG 1594 connector test kit
- 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 measured values."
- Select the measuring value "PID 13: Vehicle speed".
- Perform a road test, while a 2nd person observes 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 AEG

- To measure voltage, connect multimeter between sockets 2 (Ground -GND-) + 20 (speed signal) of test box.

Vehicles with engine code AVH, AZG, BDC

- To measure voltage, connect multimeter between sockets 2 (Ground -GND-) +54 (speed signal) of test box.

Continuation for all vehicles

- Raise vehicle at front left.
- 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. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes