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.
Circuit Description
The MIL is illuminated by PCM if diagnostics have detected certain errors related to engine performance or engine sensor status. When PCM is commanding the MIL on, voltage potential of the circuit will be low (near zero volts). When PCM is commanding the MIL off, voltage potential of the circuit will be high (near battery voltage). Primary function of PCM is to supply ground to the MIL control circuit.
DTC will set when the following conditions are present:
- MIL is requested on.
- Voltage to MIL control circuit is high (near battery voltage).
Or
- MIL is requested off.
- Voltage to MIL control circuit is low (near zero volts).
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
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.