What does code P1128 mean on Hyundai vehicles?
The ECU detects a persistent lean air-fuel mixture condition based on long-term fuel trim data.
OBD-II Code Hyundai
P1128 — Hyundai — Long Term Fuel Trim System Too Lean
The ECU detects a persistent lean air-fuel mixture condition based on long-term fuel trim data.
Common symptoms
- Loss of power
- poor acceleration
Possible causes
- Vacuum leaks
- unmetered air intake
- intake hose cracks
Initial recommendation
Inspect intake system and vacuum hoses for leaks and repair as necessary.
Safety notice
This information is for guidance only. Brand-specific codes may vary by model, year, engine, transmission and vehicle configuration. It does not replace a physical inspection or diagnosis by a qualified mechanic. If the vehicle is unsafe to operate, avoid driving it and seek professional inspection.
Analyze this code with MecaOBD
Use the app to combine Hyundai code P1128 with your vehicle's actual symptoms for more complete diagnostic guidance.
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