Checking ignition coils with output stages: Audi TT Mk1 1.8 (ARX, ARY, AUM, AUQ, …)

🧭 Before you start

Fits: Audi TT Mk1 (8N)

• Renewed: spark plug, ignition coil

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• On vehicles with dome brace, detaching of the protective cover involves disengaging and lowering the relay holder at the bulkhead. If necessary also unplug connector at air mass meter.
• To avoid damaging the catalytic converter, fuel is not to be injected whilst testing. The connectors at the injectors must therefore be unplugged.
• Connect 121-pin adapter cableV.A.G 1598/31 (test box) to wiring harness to engine control unit, but do not connect actual engine control unit .

🔧 Engine codes this applies to

📋 Procedure

1. Remove engine cover (arrows).
2. Check misfiring detection .
3. Continue with testing at cylinder indicated ⇒ "“If defective cylinder has been established”".
4. With engine running, consecutively unplug connectors at injectors and observe engine operation.
5. Or compare the spark plugs of all cylinders, paying attention to soot deposits on electrodes.

6. Exchange spark plug of defective cylinder with that of another cylinder.
7. Replace spark plug.
8. Exchange ignition coil of defective cylinder with that of another cylinder.
9. Replace ignition coil.
10. Unplug 4-pin connector (1) at ignition coil (2).
11. Connect up voltage testerV.A.G 1527 B between contact (2) and battery positive and then between contact (4) and battery positive.
12. Use current flow diagram to check wiring.
13. Check power supply.
14. Connect up multimeter (voltage measuring range) between contact (1) and earth:
15. Switch on ignition.
16. Check actuation of output stages .
17. Detach Motronic current supply relay J271(Item 1) beneath cover on left at bulkhead. [Note: On vehicles with dome brace, detaching of the protective cover involves disengaging and lowering the relay holder at the bulkhead. If necessary also unplug connector at air mass meter.]
18. Perform the following operations:
19. Check wiring from relay carrier beneath cover on left at bulkhead, contact (2) to connector at ignition coil, contact "“1”".
20. Check Motronic current supply relay J271.
21. Check actuation.
22. Unplug connectors at all injectors. [Note: To avoid damaging the catalytic converter, fuel is not to be injected whilst testing. The connectors at the injectors must therefore be unplugged.]
23. Unplug 4-pin connector (1) at ignition coil (2).
24. Connect up voltage testerV.A.G 1527 B between contacts (2) and (3) of connector.
25. Briefly operate starter.
26. Connect 121-pin adapter cableV.A.G 1598/31 (test box) to wiring harness to engine control unit, but do not connect actual engine control unit .
27. Check for open circuit and short to earth or positive in the following wiring:
28. Repair wiring if necessary.
29. Replace joint ignition coil/output stage component.

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