Vehicle Speed Signal, Checking
Vehicle Speed Signal, Checking
Special tools and equipment
- Scan tool VAG 1551 or vehicle system tester VAG 1552 with cable VAG 1551/3
- Test box VAG 1598/31
- Hand multimeter VAG 1526 or multimeter VAG 1715
- Adapter set VAG 1594
- Wiring diagram
Check conditions
- The battery voltage must be at least 11.5 V.
- Speedometer must be OK., checking speedometer:
- The selector lever of the automatic transmission must be in "P" or "N" position.
Test sequence
NOTE: To check the speed signal the vehicle must be driven. To do this a second person is necessary.
WARNING: Secure scan tool to rear seat and operate from this position.
- Connect scan tool VAG 1551 (VAG 1552). Start engine and select "Address word" 01 of engine control module. When doing this the engine must be running at idling speed.
(Connecting scan tool and selecting engine control module). Refer to "VAG 1551 Scan Tool" [1][2][3][4][5]Connecting VAG 1551 Scan Tool
Indicated on display:
Rapid data transfer HELP
Select function XX
- Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.
Indicated on display:
Read measured value block HELP
Input display group number XXX
- Press keys 0, 0 and 5 for "Display group number 5" and confirm entry with Q key.
Indicated on display: (1-4 = Display zones)
Read measured value block 5 ->
1 2 3 4
- Carry out test drive with a 2nd person to observe display.
- Observe figure displayed in display zone 3:
Specification: approx. driven speed
- Press the -> key.
- Press keys 0 and 6 for the "End output" function and confirm input with the Q key.
- Switch off ignition.
If no speed is displayed:
- Connect test box VAG 1598/31 to control module wiring harness. The engine control module remains disconnected.
- Connect multimeter to measure voltage between test box sockets 3 (terminal 15) + 54 (speed signal).
- Switch on ignition.
- Lift vehicle at front left.
- Rotate front wheel and observe voltage display.
Specification: between 0 and at least 4 Volt fluctuating
If the display does not fluctuate:
- Check wiring to speedometer/speedometer sender.