Diagnostic trouble code P0204 indicates a malfunction in the fuel injector circuit for cylinder 4. The engine control module (ECM) has detected an abnormal voltage or current in the electrical circuit that controls the injector, which may prevent the injector from delivering fuel properly.
The injector itself may be clogged, stuck open/closed, or have an internal electrical failure, causing incorrect circuit readings.
Frayed, shorted, or open wiring between the ECM and injector, or a loose/corroded connector at the injector, can disrupt the signal.
The injector's internal coil may have an open or short circuit, leading to resistance outside the expected range.
The transistor inside the engine control module that grounds the injector circuit may have failed, though this is rare and should only be considered after ruling out all other causes.
Driving with a cylinder 4 injector circuit fault can cause engine misfire, which may lead to catalytic converter damage, poor fuel economy, and potential stalling. It is best to diagnose and repair the issue promptly.
No. A wiring issue or poor connection can mimic a faulty injector. Always inspect the circuit and connector before replacing the injector to avoid unnecessary parts replacement.
The code may clear if the fault is intermittent, but the underlying problem will remain. The check engine light will likely return once the ECM detects the circuit malfunction again.
No. While a faulty ECM driver is possible, it is rare. The vast majority of P0204 cases are caused by a bad injector, wiring damage, or connector issues. The ECM should only be suspected after thorough testing of all other components.