audi Workshop Repair Guides

Audi Workshop Service and Repair Manuals

Testing a 2-wire bus system (CAN bus) > < Testing signals to and from dash panel insert
TDI®injection and glow plug system (4-cyl. unit injector)
Testing signals to and from dash panel insert
Testing signal wire (CAN bus) between engine control unit and dash panel insert

The engine control unit and the dash panel insert are connected to each other via a CAN bus. The CAN bus consists of two signal wires which are used to transmit information (e.g. engine torque, engine speed).

Test sequence

  • ‒ Connect test box V.A.G 1598/31 to wiring harness for engine control unit.Do notconnect to the engine control unit itself:
    • ‒ Connecting test box to engine control unit without protective housing=>Page 23-49.
    • ‒ Connecting test box to engine control unit with protective housing=>Page 23-51.
  • ‒ Test for open circuit and short to earth or positive in the following wiring connections:

Test box
V.A.G 1598/31
Socket

Dash panel insert

Contact

6
7

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

  • ‒ Rectify any open/short circuit as necessary.

Testing a 2-wire bus system (CAN bus) > < Testing signals to and from dash panel insert