Ignition Control Module: Description and Operation

Ignition Coils/Modules:

The ignition system on this engine uses an individual ignition coil for each cylinder. An ignition coil assembly consisting of three coils and an ignition control module, is located in the center of each cam cover. This arrangement allows the ignition coil to connect directly to the spark plug using only a boot. This eliminates the need for secondary ignition wires. There are separate ignition modules for Bank 1 and for Bank 2. Each module controls the three ignition coils for that bank of cylinders. The PCM controls ignition module operation. There are six Ignition Control (IC) circuits, one per cylinder, that connect the PCM and the ignition modules. The ignition modules also have a power feed, a chassis ground circuit and a Reference Low circuit each. The PCM causes spark to occur by pulsing the IC circuit, which signals the ignition module to trigger the ignition coil and fire the spark plug. Sequencing and timing are PCM controlled.

The ignition feed circuits are fused separately for each bank of the engine. The two fuses also supply the injectors for that bank of the engine.

This system puts out very high ignition energy for plug firing. Because there are no ignition wires, there is no energy loss due to ignition wire resistance. Also, since the firing is sequential, each coil has five events to saturate as opposed to the two in a waste spark arrangement. Furthermore, no energy is lost to the resistance of a waste spark system.