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

Test sequence

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

• ‒ → Remove engine cover panel -arrows-.
• ‒ 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:

• ‒ Connect hand-held multimeter (resistance measurement range) to spark plug connector.
• ‒ Specification: approx. 2 kω

If the specification is not obtained:

• ‒ Renew spark plug connector.

If the specification is obtained:

• ‒ 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:

Test earth connection for ignition coil:

• ‒ Unplug connector from ignition coil.
• ‒ → Test earth connection from contact 4a on the 3-pin connector to engine earth for open circuit or short circuit to positive.
• ‒ Rectify any open/short circuit as necessary.

If the earth connection is OK:

Test voltage supply to ignition coil:

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.

Test requirement:

• ● Fuse No. 229 OK (in fuse box, socket position 29)

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

• ‒ Operate starter briefly.
• ‒ Specification: approx. battery voltage

If the specification is not obtained:

Vehicles up to model year 1999:

• ‒ Check the wiring.

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

Vehicles from model year 2000 onwards:

• ‒ → Remove rubber seal from plenum chamber in direction of arrow-.
• ‒ Remove plenum chamber cover -1- from the front.

• ‒ → Remove cover for electronics box in plenum chamber -arrows-.

• ‒ → Unplug current supply relay -3-.

• ‒ Carry out the following tests (marked with dots):

• ● → Check wiring between 3-way relay carrier, plug-in position 3, contact 6 and contact 15 of ignition coil connector.
• ● Test Motronic current supply relay -J271 .

All models

If the specification is obtained:

Test activation:

• ● All ignition coil connectors connected

• ‒ Unplug 4-pin connector from output stage
  => Fitting locations overview, Page 24-5.
• ‒ → Connect voltage tester V.A.G 1527 B as follows:

• ‒ Operate starter.
• ‒ The LED should light up each time.

If the test result at one contact is not as specified:

• ‒ Switch off ignition.

• ‒ → Unplug 3-pin connector from the relevant ignition coil.

• ‒ → Test for open circuit in wiring between output stage and contact 1 of the relevant ignition coil connector.

• ‒ Rectify any open/short circuit as necessary.