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.
DTC P04C9: General Description
A cumulative fuel amount that has been injected since the last refueling should not exceed the fuel tank capacity in general as long as the fuel fill door system is fully functional since a cumulative amount of injected fuel that is monitored by the powertrain control module (PCM) is reset at the time of each refueling. When the PCM is unable to detect refueling, the cumulative amount of injected fuel monitored by the PCM eventually exceeds the fuel tank capacity because either of the following reasons: refueling was made without the fuel fill door switch being pressed or refueling was not detected by the PCM even the switch was being pressed. When this occurs, the PCM detects a malfunction of the fuel fill door system and stores a DTC.
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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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