With Manufacturer's Scan Tool

Ignition Coils With Power Output Stages, Checking







Special tools and workshop equipment required
- V.A.G 1526 A Multimeter
- V.A.G 1527 B Voltage tester
- V.A.G 1594 A Connector test kit
- V.A.G 1598/31 Test box

Work sequence

NOTE: The ignition coil and the power output stage are combined in a common component.







- Remove engine cover (arrows).

Identify an inoperative or misfiring cylinder as follows:
- Test misfire detection.

If misfires are detected:
- Continue checking indicated cylinder, see "If the faulty cylinder is recognized".

If no misfires were detected:
- Disconnect connectors from injectors in sequence with engine running, and observe how engine runs.
or
- Compare spark plugs of all cylinders with each other and check for soot on electrodes.

If the faulty cylinder is recognized:
- Replace spark plug of faulty cylinder with one from another cylinder.

If the malfunction moves with the spark plug:
- Replace spark plug.

If the malfunction remains in the same cylinder:
- Replace ignition coil from faulty cylinder with one from another cylinder.

If the malfunction moves with the ignition coil:
- Replace ignition coil.

Checking Ground (GND) connection







- Disconnect 4-pin connector -1- from ignition coil -2-.







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

Connector Measure to
terminal
2 Battery positive (B+)
4 Battery positive (B+)

- LED must light up.

If the LED does not light up:
- Check wiring connections.

If LED lights up:
Checking power supply

Requirements
- Fuses for engine electronics OK







- Connect multimeter as follows to measure voltage:

Connector Measure to
terminal
1 Engine ground (GND)

- Switch ignition on.

Specified value: approx. battery voltage (B+)

If specified value is obtained:
- Check activation of power output stages.

If specified value is not obtained:







- Remove rubber seal of plenum chamber cover in direction of arrow.
- Remove plenum chamber cover -1- from front.







- Pry off both trim caps -3- with a screwdriver.
- Undo hex nuts -4- a few turns.
- Release wiper arms -2- from pivot shaft by tilting them slightly.
- Remove hex nuts completely and remove wiper arms.
- Remove retaining clips -1- and remove air cowl grille -5-.







- Remove cover for electronics box (plenum chamber) (arrows).







- Lift off ECM retaining clip using a screwdriver (arrow) and move module to side.
- If installed, unclip Transmission Control Module (TCM) retaining clip and move module to one side.







- Disconnect power supply relay -2-.
- Perform following tests:







- Check wiring of relay carrier, electronics box, plenum chamber, position 2, terminal 8, to connector of ignition coil terminal 1.
- Check Motronic ECM power supply relay -J271-.

Checking activation of power output stages
- Disconnect all injector connectors.

NOTE: It is important to ensure that no fuel is injected during the test, as this would damage the catalytic converter. Therefore, the connectors on the injectors must be disconnected.







- Disconnect 4-pin connector -1- from ignition coil -2-.







- Connect LED voltage tester V.A.G 1527 B to terminals -2- and -3- of 4-pin ignition coil connector.
- Operate starter briefly.
- LED voltage tester must flash (flashes briefly).

If LED does not flash:
- Connect test box V.A.G 1598/31 to wiring harness for ECM; do not connect ECM. Test Box, Connecting For Wiring and Component Test







- Check for open circuit, short to positive or short to ground in following wiring connections:

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

- Repair any open/short circuit as necessary.

If no wiring malfunctions are found:
- Replace common component ignition coil with power output stage.