Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Circuit Description
Ignition signal and fail-safe signal provide crucial information in the control of ignition system timing, injector timing and fail-safe activation. Based on initial timing calculated by crankshaft and camshaft sensor signals, PCM sends an ignition signal to ignitor and uses it as a reference point to determine ignition dwell.
A circuit within ignitor controls ignition dwell and spark period by controlling power transistor switch on and off. After spark has occurred, ignitor sends an ignition fail-safe signal to PCM, confirming an ignition event has taken place. If fail-safe signal is not received by PCM, fail-safe mode is activated and fuel injector operation is ceased to prevent catalytic converter damage. DTC P1300 will set when no ignition fail-safe signal is received by PCM for 4 consecutive ignition cycles.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.