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2006-2010 KIA OPTIMA
2.7L V6•FWD•AUTOMATIC•gas
3 active safety recalls on this vehicle — view recalls
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Repairs0Labor547Torque5594Fluid6DTC893Battery1Maintenance0Recalls3
P1127moderate severityPowertrain

Long Term Fuel Trim System Too Rich

on 2006-2010 Kia Optima 2.7L V6 · FWD

What this code means

The PCM has detected that the long-term fuel trim system correction has exceeded the rich limit. Similar to P1123 but applies to the overall system-level fuel trim rather than individual bank correction.

Symptoms

  • Check Engine Light
  • Poor fuel economy
  • Black exhaust smoke
  • Rich exhaust odor
  • Rough idle

Common causes

  • Multiple leaking fuel injectors
  • Fuel pressure regulator failure
  • EVAP system purging excessively
  • Faulty MAP or MAF sensor over-reporting airflow
  • Stuck-open fuel injector

Diagnostic steps

  1. Monitor system-level fuel trim on scan tool
  2. Compare bank-to-bank fuel trims
  3. Check fuel pressure at idle and under load
  4. Test EVAP purge valve for leaking
  5. Inspect fuel injectors for leaks

Repair notes

Diagnose and repair the source of excess fuel delivery causing the rich system fuel trim.

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Other Powertrain codes on this vehicle

🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years. Spot an error? Use the Help link above — a human reads every report.
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