Audi Workshop Service and Repair Manuals

Note:

Each ignition coil is combined with its output stage as a single component.

It is not possible to test this component using conventional measuring equipment and methods.

If there is a fault in the ignition system:

• ‒ Test power supply
• ‒ Test activation of output stages
  => Page 28-6

If the tests do not reveal any faults but there is still no ignition spark:

• ‒ Renew output stage with ignition coils.

Testing power supply

• ‒ Unplug connector from ignition coils
  => Fitting locations overview, Page 24-5.
• ‒ → Connect hand-held multimeter (voltage test range) to contact 4a and to earth.
• ‒ Switch ignition on.

• Specification: approx. battery voltage

If the specification is not obtained:

• ‒ Check the wiring.

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

Testing activation of output stages

• ‒ Unplug the connectors from all four injectors.

Note:

It is important to ensure that no fuel is injected during the test as this would damage the catalytic converter. The connectors on the injectors must therefore be unplugged.

• ‒ Unplug connector on ignition coils
  => Fitting locations overview, Page 24-5.
• ‒ Switch ignition on.

• ‒ → Connect diode test lamp V.A.G 1527 to the following sockets on the connector:
• ‒ Operate starter for a few seconds.

If the specifications are not obtained:

• ‒ Switch off ignition.
• ‒ Connect test box V.A.G 1598/31 to wiring harness for engine control unit. Do not connect to the engine control unit itself.
  => Page 24-10.

Check the following wiring connections for open circuits and short to positive or earth.

• ‒ Rectify any open/short circuit as necessary.

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