Circuit Operation

With the ignition switch in RUN or START, battery voltage is applied through each of the ignition coils to the ignition control module (ICM). The ignition control module (ICM) acts as a switch to control current through the primary windings of the ignition coils. The ignition control module (ICM) is controlled by the powertrain control module (PCM). When current flow through the primary winding of each ignition coil is stopped, a high-voltage current is induced in the secondary winding of the coil and the high-voltage current flows to the spark plug.

The ignition system is controlled by inputs to the powertrain control module (PCM). The inputs include: detonation, engine RPM, accelerator position, coolant temperature, ignition timing adjustment, manifold pressure, crankshaft position and exhaust oxygen content. The automatic transmission also affects the ignition system; refer to the fuel injection system schematic for details.

The radio noise condenser 1 helps suppress electrical interference with radio reception.