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)
The MIL may also be referred to as the CHECK ENGINE light. MIL is located on the instrument cluster, just to the left of the tachometer. When ignition is first turned on, MIL should come on and remain on for 2 seconds to verify bulb and circuit operation, and then go off.
The Powertrain Control Module (PCM) monitors several different engine control system circuits. If malfunction occurs which affects vehicle emissions, a Diagnostic Trouble Code (DTC) will be stored in PCM and PCM enters limp-in mode. When DTC is stored in PCM, the PCM will turn on the MIL and MIL will remain on steady. If problem exists which does not affect vehicle emissions, a DTC will be stored in PCM but MIL will not be turned on.
If PCM detects active engine misfire severe enough to cause catalytic converter damage, MIL will flash to warn the driver of possible damage and DTC will be stored.
The PCM will turn off MIL when malfunction is not detected during 3 consecutive trips on all applications except an engine misfire or fuel system monitor.
The PCM will turn off MIL when malfunction is not detected during 3 engine misfire or fuel system monitor tests. The PCM performs engine misfire or fuel system monitor tests when engine is operating within 375 RPM and within 10 percent of the load of operating condition at which first malfunction was detected.
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:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.
