Audi Workshop Service and Repair Manuals

Note:

For testing the power supply to the engine control unit, see also "Reading measured value block", Display Group 03, display zone 2.

Test requirements:

• ● Fuse for engine control unit OK
• ● Battery voltage at least 11 V
• ● Alternator OK

• ‒ Connect test box V.A.G 1598/22 to wiring harness for engine control unit.
  
• ‒ Switch ignition on.

• ‒ Connect diode test lamp V.A.G 1527 to socket 1 (live positive supply via ignition switch) and earth.

The diode test lamp should light up.

• ‒ → If the diode test lamp does not light up, test for open circuits using the current flow diagram and rectify if necessary.

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

• ‒ If diode test lamp V.A.G 1527 lights up, connect diode test lamp to socket 1 (live positive supply via ignition switch) and socket 2 (earth connection).

• The diode test lamp should light up.

• ‒ → If the diode test lamp does not light up, test wiring for open circuits using current flow diagram and rectify if necessary.

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

• ‒ Connect diode test lamp V.A.G 1527 to socket 3 (permanent live) and earth.

• The diode test lamp should light up.

• ‒ → If the diode test lamp does not light up, test wiring between central electrics and contact 3 on control unit connector using current flow diagram. Rectify any open circuits if necessary.

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