Download 1999 Audi A6 Quattro Sedan Ignition Coil Testing and Inspection – Ignition coils and power output stage, checking NOTE: – The ignition coils and power output stage are one component. – Measuring the primary resistance of the ignition coils is not possible. – Measure secondary resistance first with ignition wires connected to the ignition coil via the spark plug connector of the respective cylinder (with this method the interference resistances of the ignition cables are also measured). – Component locations Required special tools and test equipment – Multimeter US 1119 (Fluke 83 or equivalent) – VAG 1598/22 test box – VW 1594 connector test kit Test conditions – No fuel injector malfunction stored in DTC memory Checking – Check DTC memory. – There must be no malfunctions stored – If DTC memory is not clear (malfunctions recognized): – Make necessary repairs and erase DTC memory. – Stop engine and start engine again. – Road test. – Check and erase DTC memory again. – By briefly disconnecting fuel injector connectors with engine running, check which cylinder is misfiring, or not firing at all. A misfiring cylinder can also be isolated by examining the spark plugs (for a carbon-fouled plug). – Interchange spark plug with one from cylinder that is OK. If a different cylinder now misfires: – Replace faulty spark plug. If the original cylinder misfires: – Check ignition coil. Checking ignition coils -N-, -N128- and – N158- – Disconnect 5-pin connector from ignition coil assembly. – Remove ignition wires from spark plugs. – Using multimeter and adapters from VAG 1594 connector test kit, measure resistance between both spark plug connectors of respective ignition circuit (across coil).