English-first OBD-II diagnostics Static, fast, focused lookup pages
CD CheckDTC Garage-grade fault lookup
Open P0300 Try AI Diagnose
Home / Codes / P0204
DTC code page

P0204: Injector Circuit/Open - Cylinder 4

Quick answer: The ECU detected an electrical fault in the cylinder 4 injector circuit.

Drivers also search this fault as cylinder 4 injector circuit, injector 4 open circuit, P0204 injector fault.

Severity: high Family: powertrain Related paths: 10
Meaning

What P0204 usually means

P0204 is the cylinder 4 injector-circuit fault code. It usually indicates a problem in the injector electrical path itself rather than a broad fuel-delivery complaint affecting the whole engine.

Fast triage

Start here before chasing parts

  • Scan first: save freeze-frame and pending codes before clearing anything.
  • Confirm the complaint: compare the stored code with current drivability symptoms.
  • Use context: trims, live data, and related codes usually narrow the fault faster than guesswork.
  • Work simplest to hardest: leaks, connectors, maintenance items, and known patterns before expensive components.
Initial checks

What to check first

  • Check whether P0304 is stored too, because that pairing is common when injector 4 drops out.
  • Inspect injector 4 connector for heat, oil, or coolant contamination.
  • Look for harness movement or stretch near the fuel rail and intake.
Driving risk

Can you keep driving?

If P0204 causes active stumble or a flashing MIL, reduce driving sharply. Even if the engine still runs, catalyst stress can build fast.

High urgency: If symptoms are active, reduce driving and diagnose quickly before secondary damage builds.
Likely causes

Common causes behind this code

  • Cylinder 4 injector coil failure
  • Connector corrosion, spread pins, or poor lock engagement
  • Open or short in injector 4 wiring
  • Shared injector feed instability
  • PCM driver issue after external faults are ruled out

Cause phrases often tied to this code: injector 4, wiring open, connector fault, injector coil, driver issue.

Diagnostic order

Suggested workflow

  1. Save freeze-frame data and note idle versus load behavior.
  2. Inspect injector 4 connector condition and wire routing.
  3. Verify feed voltage and command-circuit integrity at cylinder 4.
  4. Measure injector resistance to determine whether the injector coil itself failed.
  5. Road-test or idle-test until you confirm the original trigger condition no longer causes a return code.
Avoid guesswork

Common mistakes

  • Replacing ignition parts because the engine shakes like a normal misfire.
  • Skipping voltage-supply checks and blaming the injector immediately.
  • Missing contamination from nearby leaks that repeatedly damages the connector.
Repair path

Practical fix guidance

  • Repair or replace only the proven injector 4 circuit component and protect the harness against repeat failure.
  • If the injector tested bad, inspect the connector body and feed circuit before finishing the job.
  • Verify smooth running and no repeat P0204 or P0304 afterward.
Vehicle context

Affected brands in this MVP

Brand hubs help broaden internal linking now and can evolve into make-specific diagnostic notes later.

Aliases and common searches

English phrases tied to P0204

Useful when the driver knows the wording but not the exact DTC yet.

  • cylinder 4 injector circuit
  • injector 4 open circuit
  • P0204 injector fault
Related search intent

Queries this page can answer naturally

  • P0204 code meaning
  • what does P0204 mean
  • cylinder 4 injector problem
FAQ

Quick questions about P0204

Can P0204 clear and come back later?

Yes. Intermittent connector and harness faults often return only with heat or vibration.

Does P0204 mean the injector is clogged?

Not by itself. The code is about the injector circuit, not just spray flow.

Can one injector-circuit fault affect fuel trims?

Yes. A dead or inconsistent cylinder can skew oxygen-sensor feedback and fuel trims.