P0204

Cylinder 4 Injector A Circuit

Fuel injector circuit Generic OBD-II High

What it means

P0204 means the ECM detected an electrical fault in the fuel-injector control circuit for cylinder 4 — an open, short, or wiring problem in that injector's circuit. If the injector stops delivering fuel, cylinder 4 goes dead and the engine misfires, runs rough, and loses power. Because a persistent misfire can overheat the catalytic converter, this is worth diagnosing before driving far.

High

Can I keep driving? Limit driving — an injector-circuit fault can leave cylinder 4 dead, causing a misfire that dumps raw fuel into the exhaust and can damage the catalytic converter.

Real-world scan data

Seen in

4,825

scans in the past year

Found in

0.8%

of scans

1.4%

of scans that found faults

Appears alongside · share of P0204 scans

P0203in 68.7% of scans

P0201in 66.5% of scans

P0202in 64.5% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Rough idle and a misfire on cylinder 4
Reduced power and hesitation on acceleration
Raw-fuel smell or increased fuel consumption

Common causes

Most likely first

Failed fuel injector on cylinder 4 (open or shorted coil) — most commonLikely
Open or damaged wiring in the cylinder-4 injector circuitCommon
Loose or corroded injector connectorCommon
Failed injector driver in the ECM (rare)Less often

How to diagnose & fix

Work through it in order

Read freeze-frame and check for a matching cylinder-4 misfire code (P0304).
Measure the cylinder-4 injector's coil resistance and compare to the other injectors.
Inspect the injector connector and wiring for opens, shorts, or corrosion; check for the ECM's control pulse.
Replace the injector if it's electrically open or shorted, then clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0204?+

Only briefly. If the circuit fault stops cylinder 4 from firing, the resulting misfire sends unburned fuel into the catalytic converter and can ruin it. Get it diagnosed before driving much.

Can I just clear P0204?+

It will return quickly if the injector or its wiring is still faulty. Repairing the circuit or replacing the injector is what actually clears it.

Read & clear P0204 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX