Circuit Description
A Direct Ignition System (DIS) has been adopted. DIS improves ignition timing accuracy, reduces high-voltage loss, and enhances overall reliability of ignition system by eliminating distributor. DIS is a one-cylinder ignition system which ignites one cylinder with one ignition coil. In one-cylinder ignition system, one spark plug is connected to end of secondary winding. High voltage generated in secondary winding is applied directly to spark plug. Spark of spark plug passes from center electrode to ground electrode.
ECM determines ignition timing and outputs ignition signals (IGT) for each cylinder. Based on IGT signals, power transistors in igniter cuts off current to primary coil, and spark is supplied to spark plug that is connected to end of secondary coil. Igniter also sends an ignition confirmation signal (IGF) as a fail-safe measure to ECM. DTC is detected if there is no IGF signal to ECM while engine is running. See Fig 1. Possible causes are:
- Open or short in IGF or IGT1-8 circuit from ignition coil with igniter to ECM.
- Faulty No. 1-8 ignition coil with igniter.
- Faulty ignition system.
- Faulty ECM.