Ignition Coil: Description and Operation

IGNITION COILS (IC)

The ignition coil (IC) provides the voltage for 2 spark plugs simultaneously. The IC is a dual coil pack, and directly supplies voltage to each spark plug. The engine control module (ECM) will command the IC circuit ON, this allows the current to flow through the primary coil windings for the appropriate time or dwell. When the ECM commands the IC circuit OFF, this will interrupt current flow through the primary coil windings. The magnetic field created by the primary coil windings will collapse across the secondary coil windings, which induces a high voltage. The secondary coil voltage travels from the coil output terminal, through the spark plug wire, and across the spark plug gap to the engine block. The IC is not serviceable and must be replaced as an assembly. The IC consists of an ignition 1 voltage circuit, an IC 1 and 4 control circuit, and an IC 2 and 3 control circuit.