Testing ignition coils with output stages — AUDI

APP
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 -1- from ignition coil -2-.

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

Connector / Contact · Measure against
2 · Battery positive
4 · Battery positive

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:

Connector / Contact · Measure against
1 · Engine earth

Switch on ignition.
Specification: approx. battery voltage

If the specification is not obtained:

Vehicles > model year 1999:

Check the wiring.

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

Vehicles model year 2000 >:

Unplug current supply relay -2- (located under cover on left side of bulkhead).

Note:

To remove protective cover on TT Roadster vehicles, disengage and move down relay carrier on bulkhead. If necessary, also unplug connector on air mass meter.

Carry out the following tests (marked with dots):

Check wiring between contact 2 of relay carrier (located under cover on left side of bulkhead) and contact 1 of ignition coil connector.
Test Motronic current supply relay -J271 => Page
28-11
.

All models

If the specification is attained:

Test activation of output stages => Page
28-9
.

Testing activation of output stages

Unplug connectors from all 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 -1- from ignition coil -2-.

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
24-20
.

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

Connector / Contact · Test box V.A.G 1598/31 / Socket
3 (cylinder 1) · 102
3 (cylinder 2) · 95
3 (cylinder 3) · 103
3 (cylinder 4) · 94

Rectify any open/short circuit as necessary.

If no wiring fault is detected:

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