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 P1300 is set if there is no IGF1 signal (No. 1 ignitor circuit) to ECM for 8-11 consecutive IGT1 signals. DTC P1305 is set if there is no IGF2 signal (No. 2 ignitor circuit) to ECM for 8-11 consecutive IGT2 signals. Possible causes are:

• Open or short in IGF1 or IGT1 circuits.
• Open or short in IGF2 or IGT2 circuits.
• Ignitor.
• ECM.