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 IGF circuit to ensure primary switching occurred. Code is set when there is no IGF signal to ECM for 6 consecutive IGT signals during engine operation. Possible causes are:

• IGF or IGT open or short circuit from ignitor to ECM.
• Ignitor.
• ECM.