Ignition Coil: Testing and Inspection
Ignition Coils With Power Output Stages, Checking
Special tools and equipment
- VAG 1526A
- VAG 1527B
- VAG 1594A
- VAG 1598/31
Test sequence
NOTE: The ignition coil and the output stage are combined in a common component.
Identify an inoperative or misfiring cylinder as follows:
- Check misfire detection. Testing and Inspection
If misfires are detected:
- Continue checking indicated cylinder if faulty cylinder has been identified.
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 carbon on electrodes.
If the faulty cylinder has been identified:
- 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.
Check Ground connection
- Remove cover -1- on left in engine compartment.
- Unbolt coolant expansion tank (arrow).
- Disconnect electrical wiring to engine coolant level (ECL) warning switch -F66- on bottom of expansion tank.
- Lay coolant expansion tank with connected coolant hoses -1 to 3- aside.
- Remove cover -1- on right in engine compartment.
- Remove bolts (arrows).
- Remove air duct -1-.
- Disconnect EVAP canister purge regulator valve -N80- -1- from air duct.
- Remove air filter housing (arrows).
- Remove bolts (arrows) on right cylinder head.
- Disconnect 4-pin connectors -1 to 3- on ignition coils.
- Remove bolts (arrows) on left cylinder head.
- Disconnect 4-pin connectors -4 to 6- on ignition coils.
- Connect voltage tester VAG 1527 B as follows:
Connector Measure to
terminal
2 Battery positive
4 Battery positive
- LED should illuminate.
If the LED does not illuminate:
- Check wiring connections.
If the LED illuminates:
Checking power supply
Test requirements:
- Fuses for engine electronics OK
- Connect multimeter as follows to measure voltage:
Connector Measure to
terminal
1 Engine ground
- Switch ignition on.
- Specified value: approx. battery voltage
If specified value is obtained:
- Check actuation of output stages.
If specified value is not obtained:
- Switch ignition off.
- Pull off rubber seal of plenum chamber cover in direction of arrow.
- Remove plenum chamber cover -1- toward front (arrows).
- Remove cover for E-box, plenum chamber (arrows).
- Pry off engine control module retaining clip using a screwdriver (arrow) and move control module to side.
- Disconnect voltage supply relay -3-.
- Perform following tests:
- Check wiring of relay carrier, electronics box, plenum chamber, position 2, terminal 8, to connector of ignition coil terminal 1.
- Check power supply relay for Motronic engine control module (ECM) power supply relay -J271-.
Checking actuation of power output stages
- Connectors Disconnected from ignition coils
- Disconnect connectors from all injectors.
NOTE: It is important to make sure that no fuel is injected during the test, as this would damage the catalytic converter. The connectors on the injectors must be Disconnected.
- Connect voltage tester VAG 1527B to terminals 2 and 3 of connector.
- Operate starter briefly.
- LED test light should flash (very brief flashes).
If LED does not flash:
- Connect test box VAG 1598/31 to wiring harness for engine control module; do not connect engine control module. Wiring and Component Testing Using VAG1598/31 Test Box
- Check for open circuit and short to positive or ground in following wiring connections:
Connector Test box VAG 1598/31
terminal Socket
3 (cyl. 1) 102
3 (cyl. 2) 110
3 (cyl. 3) 94
3 (cyl. 4) 103
3 (cyl. 5) 111
3 (cyl. 6) 95
- Repair any open/short circuit as necessary.
If no wiring malfunction is detected:
- Replace common component ignition coil with power output stage.