A6 Quattro Sedan V6-2.7L Turbo (APB) (2000)
Ignition Coil: Testing and Inspection
Ignition Coil, Checking
Ignition Coil, Checking
NOTE: Misfiring is recognized by the On Board Diagnostic (OBD). This means a non working cylinder is stored with the cylinder number in the DTC
memory. This has an advantage in case of a malfunction the trouble shooting procedure can be started at a certain cylinder Check the DTC memory of
the Engine Control Module (ECM) before commencing trouble shooting.
Test conditions
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No DTCs stored relating to any of the fuel injectors
Determine a non working or misfiring cylinder as follows:
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With the engine running disconnect harness connectors in sequence from fuel injectors, and observe the engine performance.
or
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Compare spark plugs of all cylinders with each other and check for soot on the electrodes.
When the faulty cylinder has been identified:
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Connect hand-held multimeter (resistance measurement) to spark plug connector:
NOTE: The spark plug connector can be disconnected from the ignition coil.
Specification: approx.: 2K Ohm.
If specification is not obtained:
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Replace spark plug connector.
If specification is obtained:
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Exchange spark plug from faulty (misfiring) cylinder with one from another cylinder. Visually check spark plug for damage e.g.: cracks on
ceramic body of spark plug.
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If malfunction (misfire) occurs now on other cylinder, replace spark plug.
If the malfunction remains at the same cylinder:
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Exchange ignition coil from faulty (misfiring) cylinder with one from another cylinder. Visually check ignition coil for damage (ignition coil could
be cracked or bursted)
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If malfunction occurs now on other cylinder, replace ignition coil.
If malfunction remains at the same cylinder.
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Disconnect harness connector from ignition coil.
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Check Ground (GND) connection between socket 4a and engine Ground (GND) for open circuit and short circuit to B+.
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Repair any open/short circuit as necessary.
If the Ground (GND) connection is OK.