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

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.

Work sequence

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

WARNING: Secure scan tool (st) on the rear seat and have it 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: Check measured values.'
- Select measuring value "PID 13: Vehicle speed".
- Perform a road test, and have 2nd person observe indication on 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) + 20 (speed signal) of test box.

Vehicles with engine code AVH, AZG, BDC, BEV, BGD
- To measure voltage, connect multimeter between sockets 2 (Ground) +54 (speed signal) of test box.

Continued for all vehicles
- Lift left front wheel.
- Switch ignition on.
- Rotate front wheel, 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.