Circuit Description

Circuit Description
With the ignition switch in ON or START, battery voltage is applied to the ignition coils. As the crankshaft turns, the PCM receives the signal of CKP and CMP sensor. Based on these inputs signal, the PCM controls the current through the ignition coils by turning the power transistor (built-in ignition coil) on and off.

When current flow through the primary winding is stopped (at the moment of power transistor turn off), a high voltage is induced in the secondary winding of the ignition coil. The high voltage is applied to the two spark plugs that are connected in series.

The ignition failure sensor is connected between the ignition coil fuse and ignition coils to detect ignition failure.