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.
DTC 46 - Mil (Service Engine Soon Light) Circuit Fault: Notes
The MIL (SERVICE ENGINE SOON) should always light when the ignition is on and the engine is not running for 2 seconds. The PCM controls the MIL and makes it light by providing a ground path. DTC 46 will set when no ignition voltage on the MIL (SERVICE ENGINE SOON light) control circuit when the PCM is requesting the MIL on. PCM will default to no MIL.
- This step checks the PCM's ability to command the MIL.
- This step determines if an open is present in the ignition feed circuit.
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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.