Volkswagen Workshop Service and Repair Manuals

Special tools, testers, measuring instruments and auxiliary items required

• ◆ Fault reader V.A.G 1551 or vehicle system tester V.A.G 1552 with cable V.A.G 1551/3
• ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
• ◆ Test box V.A.G 1598/18
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram

Test conditions

• ● Speedometer OK., checking:

=> Repair group 90; Electrical system

Test sequence

Note:

To check the speed signal the vehicle must be driven. To do this a second person is necessary.

• ‒ Connect fault reader V.A.G 1551 (V.A.G 1552). Start engine and select "Address word" 01 of engine control unit. When doing this the engine must be running at idling speed.
  (Connecting fault reader and selecting engine control unit .)

• ‒ Press keys 0 and 8 for the function "Read measured value block" and confirm entry with Q key.

• ‒ Press keys 0, 0 and 4 for "Display group number 4" and confirm entry with Q key.

• ‒ Carry out test drive and when doing this use a second person to observe display.
       Specification: Display = approx. speedometer
• ‒ Press the ⇒key.
• ‒ Press keys 0 and 6 for the function "End output" and confirm entry with the Q key.

If the display does not change:

• ‒ Switch off ignition.
• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.
• ‒ Set multimeter scale to measure voltage and connect between test box sockets 1+36.
• ‒ Switch on ignition.
• ‒ Lift front left-hand wheel.
• ‒ 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 or to speedometer sender.

=> Current flow diagrams, Electrical fault finding and Fitting locations binder