Audi Workshop Service and Repair Manuals

Special tools and workshop equipment required

• ◆ V.A.G 1526 A
• ◆ V.A.G 1527 B
• ◆ V.A.G 1594 A
• ◆ V.A.G 1598/31

Note:

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

• ‒ → Remove engine cover panel -arrows-.

The procedure for identifying an inoperative or misfiring cylinder is as follows:

• ‒ Unplug the connectors from the injectors in turn with the engine running, and observe how the engine runs.

• or

• ‒ Compare the spark plugs of all cylinders with each other and check for soot on the electrodes.

When the defective cylinder has been identified:

• ‒ Swap spark plug of defective cylinder with one from another cylinder.

If the fault moves with the spark plug:

• ‒ Renew spark plug.

If the fault remains in the same cylinder:

• ‒ Swap ignition coil of defective cylinder with one from another cylinder.

If the fault moves with the ignition coil:

• ‒ Renew ignition coil.

If the fault remains in the same cylinder:

Testing earth connections

• ‒ Unplug 4-pin connector from ignition coil.

• ‒ → Connect voltage tester V.A.G 1527 B as follows:

• ‒ The LED should light up.

If the LED does not light up:

• ‒ Check the wiring.

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

If the LED lights up:

Checking voltage supply

• ‒ → Connect multimeter (voltage measurement range) as follows:

• ‒ Switch on ignition.
• ‒ Specification: approx. battery voltage

If the specification is not obtained:

• ‒ Check the wiring.

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

If the specification is still not attained:

• ‒ Test activation of output stage .

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 4-pin connector from ignition coil.

• ‒ → Connect voltage tester V.A.G 1527 B to contacts 2 and 3 of the connector.
• ‒ Operate starter briefly.
• ‒ The LED should flash briefly.

If the specifications are not obtained:

• ‒ 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 24-16.

• ‒ → Test for open circuit and short to positive or earth in the following wiring connections:

• ‒ Rectify any open/short circuit as necessary.

If no wiring fault is detected:

• ‒ Renew ignition coil with output stage (combined as a single component).