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.
Malfunction Indicator Light (MIL)
MIL may also be referred to as Service Engine Soon light. If all systems are normal, immediately after ignition switch is turned on, MIL will illuminate for 5 seconds, then go out. When PCM determines an emissions related malfunction exists, PCM will turn the MIL on. If PCM determines that the malfunction no longer exists, it will turn the MIL off.
If MIL will not come on for bulb check or MIL stays on with no Diagnostic Trouble Codes (DTCs) present, diagnose MIL circuit malfunction. See MALFUNCTION INDICATOR LIGHT (MIL) under DIAGNOSTIC CIRCUIT CHECK.
NO RELATED
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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.