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.
Code 41, Ignition Signal Circuit, No Signal: Notes
ECM receives an ignition signal when ignition switch is turned to ON position. When ignition is turned to START position, this signal is toggled on and off through ignitor. As this signal is toggled on and off, so is ignition coil, thus inducing a voltage in secondary coil of ignition coil. Induced voltage is used to fire spark plugs.
Code 41 sets when toggled ignition signal is not present at ECM within 3 seconds of cranking.
- Checks for power to ignition coil.
- Checks for a poor connection and a faulty ignition coil.
- Checks for an open in Brown/White wire to noise suppressor filter.
- Checks for a poor connection and a faulty noise suppressor filter.
- Checks for an open in Brown wire to ECM.
- Checks for an open in Brown/White to ignitor.
- Checks ignitor for good ground.
- Checks if ECM is toggling ignition signals. Either an open, a short to ground or a faulty ECM or ignitor is at fault.
Use the Manual With the Right Hardware
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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.
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