Circuit Description

WARNING: This page is about a different car, the 2003 Toyota Camry Solara. However, it is still accessible from the selected car via links, so may be relevant.

A direct ignition system (DIS) has been adopted. The DIS improves the ignition timing accuracy, reduces the high-voltage loss, and enhances the overall reliability of the ignition system by eliminating the distributor. The DIS is a 1-cylinder ignition system which ignites 1 cylinder with 1 ignition coil. In the 1-cylinder ignition system, the spark plug is connected to the end of the secondary winding. High voltage generated in the secondary winding is applied directly to the spark plug. The spark of the spark plug passes through from the center electrode to the ground electrode.

The ECM determines the ignition timing and outputs the ignition signals (IGT) of each cylinder. Based on the IGT signals, the lower transistors cut off the current to the primary coil in the ignition coil. At the same time, the igniter also sends an ignition confirmation signal (IGF) as a fail-safe measurement to the ECM.

Detecting condition of DTC is when there is no IGF signal to the ECM while the engine is running.