P0204

Injector Circuit Malfunction - Cylinder 3

Powertrain Fuel and Air Metering Fuel Injector Circuit 🟡 Moderate — Fix within a week ⚠️ Drive with Care
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What This Actually Means

In plain language — no jargon

The fuel injector for cylinder 3 isn't working properly—either it's not opening, closing, or receiving the right electrical signal. Think of it like a water sprinkler that won't turn on or off correctly.

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Symptoms You May Notice

3 known symptoms for this code
Rough idle or misfiring on cylinder 3
Reduced fuel economy and power loss
Check engine light illuminated
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How Your ECU Detects This

Technical sensor logic and voltage thresholds

The ECU monitors the injector's electrical circuit by measuring voltage and current during the opening/closing cycle. It compares the injector's response time and electrical resistance against expected thresholds to detect opens, shorts, or resistance faults in the circuit.

Voltage & Parameter Thresholds

ParameterNormal RangeFault Condition
Injector Voltage 12V when activated Below 10V or no voltage present
Injector Circuit Resistance 12-16 ohms Above 20 ohms or infinite (open circuit)
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Diagnostic & DIY Fix Guide

Check these in order — from cheapest to most complex
1
Fuel injector connector
Inspect and reseat the connector on cylinder 3's injector to ensure good electrical contact.
2
Fuel injector wiring harness
Check wires for corrosion, damage, or loose connections between the injector and ECU using a multimeter.
3
Fuel injector
Replace the injector for cylinder 3 if connector and wiring are clean and voltage is present.
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When to See a Professional Mechanic

Not all fault codes are safe to DIY

Code P0204 is a moderate fault. You can generally drive to a workshop, but avoid long trips or high-load driving (motorway, uphill towing) until it is diagnosed. If the code keeps returning after clearing, or if you notice the symptoms listed above worsening, do not delay professional diagnosis. Many moderate codes have multiple possible root causes — a mechanic with live OBD data can identify the exact fault more efficiently than part-by-part trial and error.

Safety note: OBD-II codes identify the system or circuit where a fault was detected — they do not always identify the exact failed component. A professional mechanic using live sensor data will diagnose the root cause more accurately than replacing parts based on the code alone.
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How to Clear Code P0204

What happens after you fix the fault

Once the fault is repaired, P0204 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.

The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.

✅ Safe to Clear When
  • Fault has been diagnosed and repaired
  • You want to confirm the repair worked
  • Code appeared after a sensor was cleaned
⚠️ Do Not Clear When
  • Preparing for an emissions/PUC test
  • Root cause is still undiagnosed
  • Check engine light is flashing
Emissions test note: Clearing codes resets OBD readiness monitors. Most vehicles need 50–100 km of mixed driving before monitors complete. Do not clear codes immediately before an emissions or PUC inspection.