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 ignition signal when ignition switch is turned to ON position. When ignition is in START position, this signal is toggled on and off through ECM. As this signal is toggled on and off, it induces a voltage in secondary coil of ignition coil. This induced voltage is then used to fire spark plugs.
Code 41 will set if the toggled ignition signal is not present at the ECM within 3 seconds of cranking.
- Checks for power at ignition coil.
- Checks for poor connection or for a faulty ignition coil.
- Checks for poor connection or for a faulty ECM.
- Checks for faulty noise suppressor filter.
- Checks for an open or short circuit to ground in wires between ignition coil, noise suppressor filter and ECM.
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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