Circuit Description

The ECM uses pick-up coil input signals to switch primary ignition circuit on and off. Primary circuit is turned off when ECM delivers a signal to ignitor on the IGT wire, causing ignition coil to fire spark plug. After delivering a command to turn off primary circuit on IGT wire, the ECM monitors Ignition Confirmation Signal (IGF) circuit to ensure primary switching occurred. If IGF signal is not input to ECM, the ECM will stop fuel injection as a fail safe function. DTC is set if there is no IGF signal to ECM for 2 or more ignition cycles and this is repeated 3 times during 6 consecutive IGT signals with engine running. Possible causes are:

• Open or short in IGF or IGT circuit.
• Faulty ignitor.
• Faulty ECM.