1. Using a distributorless ignition system tester, connect the tester clip to ground and high voltage wire, and while turning the engine over with the starter, observe the tester electrode to determine if there is a spark.
2. If a spark is present, then voltage is applied to the spark plug. Similarly check up presence of a spark on other cylinders.
3. If there is no spark or it skips, check the voltage at the ignition coil.
4. If there is still no spark, check the camshaft and crankshaft position sensors.
5. If there is still no spark, check the signal from the ignition unit to the coils. Remove the connectors from each coil and connect the LED probe. When turning the engine with a starter, observe the probe, which should blink, which indicates the receipt of signals from the ignition unit to the coil.
6. If there is still no spark, replace the ignition unit.