Audi Workshop Service and Repair Manuals

Note:

The signal generated by engine speed sender -G28 is processed by the engine control unit and transmitted via contact 37 (on the engine control unit) to various electronic systems, e.g. the air conditioner control unit, automatic gearbox and ABS/EDL. These systems monitor the engine speed signal and the wiring.

To obtain engine speed, proceed as follows:

• ‒ Connect vehicle diagnostic, testing and information system VAS 5051 (or fault reader V.A.G 1551) and select engine electronics control unit by entering address word "01" ( .)
  When doing this the ignition must be switched on.

• ‒ Test all control units for a missing rpm signal via the "Automatic test sequence."
• ‒ Press the 0 key twice to select "Automatic test sequence" function and confirm entry by pressing Q key.

No faults relating to a "missing engine speed signal" should be stored in any of the control units.

If one of the control units indicates a fault:

• ‒ Test for open circuit or short circuit between engine control unit and the control unit concerned.

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