What does code P1123 mean on Hyundai vehicles?
The ECU detects a rich air-fuel mixture based on long-term fuel trim data.
OBD-II Code Hyundai
P1123 — Hyundai — Long Term Fuel Trim (Additive) Mixture Too Rich
The ECU detects a rich air-fuel mixture based on long-term fuel trim data.
Common symptoms
- High fuel consumption
- fuel odor
Possible causes
- Leaking injector
- faulty oxygen sensor
- fuel pressure issues
Initial recommendation
Inspect injectors, oxygen sensor operation and fuel pressure.
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 P1123 with your vehicle's actual symptoms for more complete diagnostic guidance.
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