With Manufacturer's Scan Tool
Vehicle Speed Signal, Checking
Special tools, workshop equipment, testers, measuring instruments and auxiliary items required
- VAG 1551 Scan tool (or VAG 1552) with VAG 1551/3 adapter cable
NOTE: All functions which could previously be performed with VAG 1551/1552 can also be performed with the VAS 5051.
- VAG 1526 Hand multimeter or VAG 1715 multimeter
- VAG 1594 Adapter set
- VAG 1598/31 test box
- Electrical Wiring Diagrams
Test prerequisites
- The fuses must be OK.
- The battery voltage must be at least 11.5 V.
- All electrical accessories, e.g. lights and rear window heating must be switched off.
- If the vehicle is equipped with air conditioning, this must be switched off.
- Selector lever must be in position "P" or "N" on vehicles with an automatic transmission.
- The speedometer must be OK.
Checking speedometer:
- No Diagnostic Trouble Code (DTC)s must be stored in DTC memory.
Reading Diagnostic Trouble Codes
Test sequence
NOTE: To check the vehicle speed signal, the vehicle must be driven. To do this a second person is necessary.
WARNING: Secure Diagnostic Trouble Code (DTC) reader to rear seat and operate from this position.
- Connect VAG 1551 Scan tool (or VAG 1552) and select engine electronics control module with the "Address word" 01. When doing this the engine must be running at idle speed: ((VAG 1551 and Motronic Engine Control Module (ECM) -J220-, connecting and selecting).
[1][2][3]Connecting VAG 1551 Scan Tool
Indicated on display:
Rapid data transfer HELP
Select function XX
- Press buttons -0- and -8- for function "Read measured value (data) block" and confirm entry with -Q- button.
Indicated on display:
Read measured value block
Input display group number XXX
- Press buttons -0-, -0- and -5- for "Display group number 5" and confirm entry with -Q- button.
Indicated on display: (1 to 4 = display zones)
Read measured value block 5 ->
1 2 3 4
- Carry out road test with a 2nd person to observe display.
Observe the valid safety precautions when carrying out a road test.
[1][2]Technician Safety Information
- Observe figure displayed in display zone 3:
Specification: approx. driven speed
- Drive slower. The displayed value must decrease.
- Press the -> button.
- Press buttons -0- and -6- for function "End output" and confirm entry with the -Q- button.
- Switch off ignition.
If no speed is indicated or the display values do not reduce when driving at a lower speed:
- Remove wiper arms and cowl panel:
- Connect VAG 1598/31 test box to control module wiring harness. The Motronic Engine Control Module (ECM) -J220- remains disconnected.
- Connect multimeter to measure voltage between test box sockets 1 (ground) and 54 (vehicle speed signal) using adapter cables from VAG 1594.
- Raise vehicle at front left.
- Switch on ignition.
- Rotate front wheel and observe voltage display.
Specification: 0.0... at least 4.0 V fluctuating
NOTE: Front right wheel must not turn, if necessary, hold to prevent it from turning.
If the display does not fluctuate:
- Check wiring from test box socket 54 to instrument cluster for open/short circuit referring to Electrical Wiring Diagrams:
- Check DTC memory, repair malfunctions if necessary and then erase DTC memory.
Reading Diagnostic Trouble Codes
- Read readiness code. If the DTC memory has been erased or the Motronic Engine Control Module (ECM) -J220- was disconnected from battery positive (B+), the readiness code must be generated again.
Monitors, Trips, Drive Cycles and Readiness Codes
Monitors, Trips, Drive Cycles and Readiness Codes