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.
Chart A-1, Won't Flash Code 12, No Check Engine Light: Notes
There should always be steady CHECK ENGINE light when the ignition is on and engine is off. Battery voltage is supplied directly to the light bulb. The ECM controls the light and turns it on by providing a ground path through the Purple wire.
- ECM battery feed terminals B1 and C16 are protected by a fusible link in fuse/relay block, near battery.
- If ECM terminals B1 and C16 have voltage, then either ECM grounds or ECM is faulty.
- Using test light connected to 12 volts, probe each of the system ground circuits to ensure good ground is present.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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.