Operation

^ When crankshaft position sensor and camshaft position sensor signal is input to engine control module, engine control module makes ON-OFF control of power transistors one by one.

^ When power transistor A is turned from ON to OFF, the spark plugs of No.1 and No.4 cylinders spark. Turning of power transistor B from ON to OFF will produce sparking in spark plugs of No.2 and No.5 cylinders. Furthermore, when power transistor C is turned from ON to OFF, sparking is produced in spark plugs of No.5 and No.6 cylinders.

^ When power transistor is turned off, high voltage is generated in primary winding of ignition coil which induces even higher voltage in the secondary winding, causing a spark at the spark plug(s).