Ignition System: Description and Operation

Ignition timing is controlled by the electronic control ignition timing system. The standard reference ignition timing data for the engine operation conditions are programmed in the memory of the Engine Control Module (ECM).
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 this way.