Vehicle Speed Sensor: Testing and Inspection

For vehicles built after 10-90 starting with control unit:
49 states: 8A0 907 404
California: 893 907 404Q

NOTE: For vehicles built before 9-90, check the speedometer speed signal using Electrical Test step 21.

For vehicles with manual transmission:

- place shift lever in neutral position

For vehicles with automatic transmission:

- place selector lever in "N" position
- raise left front wheel







- connect VAG 1551 Diagnostic Tester using VAG 1551/1 adaptor wire as follows:
- first connect black connector from VAG 1551/1 to black diagnostic connector 1
- after display "VAG SELF-DIAGNOSIS" appears, connect white connector from VAG 1551/1 to brown and/or white diagnostic connector 2

If display does not appear; do not connect white connector

- check voltage supply to VAG 1551 using wiring diagram

- switch ignition ON
- press 1 button to enter "rapid data transfer"
- press 0 and 1 for address word "engine electronics"
- press Q button to enter input
- press --> button
- press 0 and 8 buttons to obtain "Read measurement block" function
- press Q button to enter input
- display will appear as shown

Read measurement block HELP
Input display group number XX

- press 0 button twice to select display group 00

- display will appear as shown

Read measurement block Q
Input display group number 00

- press Q to enter input
- display shows channels 1 through 10

Read measurement block -->
1 2 3 4 5 6 7 8 9 10

- observe speed signal value in channel 8
- manually rotate left front wheel
- value must fluctuate between 0 and 1 minimum

If specified values is obtained:

- press --> button
- press 0 and 6 buttons to enter "end output" function
- press Q button to enter input

If specified values are not obtained:

- perform multifunction indicator troubleshooting
- read and then erase Fault memory