Cylinder 3 - Injector Restricted
What it means
P02A4 means the fuel injector on cylinder 3 is restricted — it can't flow the fuel the module expects, usually from clogging or deposits. That leaves cylinder 3 running lean, which shows up as rough running or a misfire. It's typically resolved by cleaning or replacing the affected injector rather than by clearing the code.
Can I keep driving? The engine runs, but a restricted cylinder-3 injector starves that cylinder of fuel — expect rough running and possible misfire, so address it before it worsens.
Real-world scan data
Appears alongside · share of P02A4 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 or a misfire on cylinder 3
- Hesitation or reduced power under load
- Hard starting or a lean condition on that cylinder
Common causes
Most likely first
- Clogged or restricted fuel injector on cylinder 3Likely
- Fuel deposits or contamination narrowing the injector sprayCommon
- Low or uneven fuel pressure reaching the injectorCommon
- Poor-quality or dirty fuelLess often
- Weak injector coil or partial internal faultLess often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check cylinder-3 fuel trim and any misfire counts.
- Run an injector-balance or flow test to confirm cylinder 3 is delivering less fuel.
- Try a professional injector cleaning or a quality detergent additive for light restriction.
- Verify fuel pressure and rule out a supply restriction.
- Replace the cylinder-3 injector if cleaning doesn't restore flow, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P02A4?+
Can I just clear P02A4?+
Related codes
Read & clear P02A4 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.