Circuit Description

ECM determines ignition timing and outputs ignition signals (IGT) for each cylinder. Based on IGT signals, ignitor controls primary ignition signals (IGC) for all ignition coils. Ignitor also sends an ignition confirmation signal (IGF) as a fail-safe measure to ECM. DTC is set when there is no IGF signal to ECM for 6 consecutive IGT signals during engine operation. Possible causes are:

• IGF or IGT circuit from ignitor to ECM is open or shorted.
• Defective ignitor.
• Defective ignition coil.
• Defective ECM.