Vehicle Speed Sensor: Testing and Inspection
Additional signals, checking
Vehicle Speed Signal, checking
Special tools, testers, measuring instruments and auxiliary items required
- Scan Tool VAG 1551 with cable VAG 1551/3B
- VAG 1598/22 Test Box
- Fluke 83 Multimeter
- VW 1594 Adaptor kit
- Wiring diagram
Checking conditions
- Battery Voltage must be 11.5 Volts minimum
- Speedometer must be OK
Test sequence
NOTE: To check the Vehicle speed signal, the vehicle must be driven, thus requiring a second technician.
WARNING!
Secure scan tool to rear seat and operate from this position.
- Connect VAG 1551/1552 Scan Tool, Refer to "Scan Tool Testing", [1][2][3]Reading and Clearing Diagnostic Trouble Codes
- Start engine and let idle
- Press 0 and 1 buttons to select "Address word" 01 "Engine electronics"
Display will appear as shown
Rapid data transfer HELP
Select function XX
- Press 0 and 8 buttons to select Function 08 "Read measuring value block"
- Press Q button to enter input
Display will appear as shown
Read measuring value block HELP
Input Display group number XXX
- Press 0, 0 and 5 buttons to select "Display group 5"
- Press Q button to enter input
Display will appear as shown (1 to 4 Display zones)
Read measuring value block 5 ->
- Perform test drive with a 2nd technician to observe display.
- Observe figure shown in display zone 3
- Specification: approx. driven speed
- Press -> button.
- Press 0 and 6 buttons to select Function 06: "End data transfer"
- Press Q button to enter input
- Switch OFF ignition.
Continuation
If NO speed indicated or displayed values reduce when driving slowly
- Connect VAG 1598/22 Test Box to Engine Control Module harness connector.
- Switch Multimeter to Voltage measurement range
- Connect Multimeter between Test Box sockets 2 + 20.
- Switch ON ignition.
- Lift vehicle at front left.
- Rotate front wheel and observe Voltage Display.
- Specification: between 0 and at least 4 Volts fluctuating
If value does not fluctuate:
- Check wiring to speedometer / speedometer sensor.