The ignition timing data for the engine operating conditions are programmed in the memory of the Powertrain Control Module (PCM). The engine conditions (speed, load, warm-up condition, etc.) are detected by the various sensors. Based upon these sensor signals and the ignition timing data, signals to interrupt the primary current are sent to the power transistor. The ignition coil is activated and timing is controlled at the optimum point. Misfires can be caused by lack of combustion in a cylinder due to absence of spark.
- Check that all wires are connected.
- Check for spark through the spark plug wire.
- Check voltage at the ignition coil packs.