Test Conditions Audi A8 D3

1. No DTCs stored relating to any of the fuel injectors

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

1. Disconnect harness connectors from fuel injectors in sequence with engine running, and observe how engine runs. or
2. Compare spark plugs of all cylinders with each other and check for soot on electrodes.

When the faulty cylinder has been identified

1. Swap spark plug of faulty cylinder with one from another cylinder.

If the malfunction moves with the spark plug

1. Replace spark plug.

If the malfunction remains in the same cylinder

1. Swap ignition coil of faulty cylinder with one from another cylinder.
2. If malfunction moves now to other cylinder, install new ignition coil.

If the malfunction stays at the same cylinder, test Ground (GND) connection of ignition coil.

Scheme 1

1. Display 4-pin connector from relevant ignition coil.
2. Check Ground (GND) connection between socket 4 on the 4 -pin connector and engine Ground (GND) for open circuit and short circuit to positive.
3. Repair any open/short circuit as necessary.

If the Ground (GND) connection is OK, test the voltage supply to the ignition coil. See CHECKING VOLTAGE SUPPLY TO IGNITION COIL .

Scheme 2

1. Connect hand-held multimeter (voltage range) to following socket on connector: IGNITION COIL CIRCUIT TEST - VOLTAGE SUPPLY 4-pin connector on wiring harness, socket Specification 1 + Ground (GND) Battery voltage
2. Operate starter. Specification: approx. battery voltage

If the specification is not obtained

1. Check continuity of wiring from socket 1 to fuel pump relay via fuse. Repair open circuit if necessary. See SYSTEM WIRING DIAGRAM .

If the specification is obtained

1. Check output stage. See «POWER OUTPUT STAGES FOR IGNITION COILS, CHECKING»(ref-216439-S30030772822006020800000) .