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.
Feedback System Functional Check
- Turn cancel/check switch on. See Fig 1 . Turn ignition on, but do not start engine. "CHECK ENGINE" light should be on (not flashing). If light is not on, check and repair bulb and/or circuit.
- With "CHECK ENGINE" light operating, start engine and warm to normal operating temperature. Increase engine speed up to 1500-2000 RPM. "CHECK ENGINE" light will flash if system is operating properly. If light does not flash, check the following components:
- Oxygen sensor
- Mixture control solenoid valve
- Coolant switch
- Idle and Wide Open Throttle (WOT) switches
- Electronic Control Module (ECM)
If system is operating properly, turn cancel/check switch off. Light should go out. Stop engine and repeat code retrieval procedure if necessary.
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.
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