Vehicle speed signal, checking

If the speedometer shows an incorrect reading, first check whether the signal is received by the speedometer.

• Connect VAS 5051 tester or VAG 1551 Scan Tool (ST). See VAS 5051 TESTER OR VAG 1551 SCAN TOOL, CONNECTING AND SELECTING FUNCTIONS .
• Read Measuring Value Block. See READ MEASURING VALUE BLOCK (FUNCTION 07) .
• Press buttons -0-, -0- and -1- to input display group number 001, and press -Q- button to confirm input.
• Road test vehicle.

If the VAG 1551 scan tool displays the speed, but the speedometer in the instrument cluster does not, then the instrument cluster is malfunctioning and must be replaced.

If the VAG 1551 scan tool also does not display a speed, then the signal must be checked at the multi-pin connector of the instrument cluster.

• Remove instrument cluster. See INSTRUMENT CLUSTER, REMOVING AND INSTALLING  .
• Connect VAG1598 to gray 32-pin connector using the VAG1598/25 adapter.
• Perform an acoustic continuity test of wire between socket 7 and vehicle ground using multimeter (Fluke 83 or equivalent).

Test sequence:

Whistle of the continuity tester must switch on and off several times when vehicle is rolled slightly forward and backward (approx. 1m).

Wire connection to speed sensor must be checked if test is not OK.

• Check wire connection according to wiring diagram.

  See appropriate System Wiring Diagram article.

Speed sensor must be replaced if wire connection is OK.