Ignition Coil: Description
WARNING: This page is about a different car, the 2004 Kia Amanti. However, it is still accessible from the selected car via links, so may be relevant.
The ignition power transistor functions to control the ignition timing by controlling the ignition coil primary current through signals from the ECU. The ignition coil has the firing order of (#1/#4), (#2/#5), (#3/#6) and is controlled by the power TR built in the ECU.