Understanding P0174 on Your 2024 Hyundai Sonata
Your 2024 Hyundai Sonata has triggered a P0174 code, meaning the engine control module has detected a lean fuel condition. The 2024 Sonata uses a 2.5-liter Smartstream inline-4 engine producing 191 horsepower, paired with an 8-speed automatic transmission. As an inline-4, this engine has a single bank, but P0174 can appear based on how the ECU interprets fuel trim and oxygen sensor data.
Running lean means the combustion chambers are receiving too much air relative to fuel. The ECM has been adding fuel to correct this, but the corrections have exceeded the normal operating range.
What Symptoms to Expect
- Check engine light illuminated
- Rough or inconsistent idle
- Reduced acceleration performance
- Lower fuel economy than the Sonata's rated 28/38 MPG
- Hesitation when stepping on the gas
- Possible engine surging or misfires
Most Likely Causes
- Vacuum Leak (40% likelihood) -- Even on a new vehicle, intake gaskets, PCV hoses, or clamps can develop leaks from manufacturing variations or assembly issues.
- MAF Sensor Issue (25% likelihood) -- Contamination from aftermarket air filters or PCV system issues can affect mass airflow sensor accuracy.
- Fuel Delivery Problem (20% likelihood) -- A defective fuel pump, restricted filter, or faulty regulator can reduce fuel supply.
- Fuel Injector Restriction (15% likelihood) -- Manufacturing defects or contaminated fuel can restrict injector flow on a new vehicle.
Diagnostic Steps
- Read all stored codes -- Check for P0171, P0101, or misfire codes.
- Analyze fuel trims -- LTFT above +15% confirms the lean condition.
- Smoke test the intake -- Find any vacuum leaks in the 2.5L intake system.
- Test MAF sensor -- Verify readings match Hyundai's specs for the Smartstream 2.5L.
- Check fuel pressure -- Ensure the fuel system delivers proper pressure.
Repair Options
- Fix vacuum leaks -- Replace gaskets, hoses, or tighten clamps.
- Service MAF sensor -- Clean or replace.
- Repair fuel delivery -- Replace pump, filter, or regulator.
- Service fuel injectors -- Clean or replace restricted injectors.
Estimated Repair Costs
- Vacuum leak repair: $100 - $350
- MAF sensor replacement: $150 - $360
- Fuel pump replacement: $420 - $750
- Fuel injector service: $180 - $500
Your 2024 Sonata is fully covered under Hyundai's comprehensive warranty. All repairs should be handled by the dealer at no cost.
Prevention Tips
- Use only OEM or quality equivalent air filters
- Fill up with top-tier gasoline
- Report any drivability concerns to your dealer while under warranty
- Follow the Hyundai maintenance schedule
- Check for applicable TSBs and recalls