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. See Fig 1.
ECM determines ignition timing and outputs ignition signals (IGT) for each cylinder. Based on IGT signals, power transistors in igniter cut off current to primary coil in ignition coil 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.
If DTCs are set there is no IGF signal to ECM while engine is running. Possible causes are:
- Faulty ignition system.
- Open or short in IGF and IGT1-6 circuit from ignition coil assembly circuit.
- Faulty coil assembly.
- Faulty ECM