Understanding P0174 on the 2024 Acura RDX
Your 2024 Acura RDX features the same proven 2.0L turbocharged four-cylinder (K20C4) producing 272 horsepower. When P0174 appears, the powertrain control module has detected a lean condition — the air-fuel mixture is running with too much air or too little fuel. On the inline-four K20C4, this code indicates a generalized lean state that has pushed long-term fuel trims beyond the normal correction range.
Symptoms You May Experience
- Check engine light illuminated
- Idle roughness or slight surging
- Hesitation during acceleration, especially from low RPM
- Reduced turbo boost feel
- Lower fuel economy than expected
Causes of P0174 on the 2024 RDX
1. Turbo Boost Leaks
The charge air system on the K20C4 includes the turbocharger compressor outlet, intercooler piping, and throttle body inlet. Any leak after the MAF sensor creates a discrepancy between measured and actual airflow. On a 2024 model, factory assembly issues like an undertorqued clamp or a charge pipe coupler that was not fully seated could be responsible. A boost leak test is the fastest way to identify these issues.
2. MAF Sensor Contamination
Even on a brand-new vehicle, the MAF sensor can become contaminated if an oiled aftermarket air filter was installed or if factory assembly left residue in the intake tract. The hot-wire element underreads airflow when coated, causing the PCM to deliver insufficient fuel. MAF sensor cleaning takes minutes and costs under $15 for a can of cleaner.
3. Fuel System Under-Delivery
The K20C4's direct injection system operates at very high pressures (up to 200+ bar). A high-pressure fuel pump not reaching target pressure or a fuel injector with a restricted spray pattern will result in lean combustion. This is uncommon on a new vehicle but can occur with poor fuel quality or a manufacturing defect.
4. Intake Manifold Gasket Leak
The intake manifold on the K20C4 uses a multi-layer gasket where it meets the cylinder head. A gasket that was pinched during assembly or has a defect can allow unmetered air into the combustion chambers. This type of leak typically produces a consistent lean condition at all engine speeds.
Diagnostic Steps
- Read all DTCs and freeze frame data — note fuel trim values and engine conditions at code set
- Perform a boost leak test with 15-20 psi of regulated air
- Inspect all charge pipe connections, clamps, and couplers
- Clean the MAF sensor with approved cleaner
- Monitor fuel rail pressure via scan tool at idle and under load
- Check intake manifold gasket area with a smoke machine if boost test is clean
Repair Cost Estimates
The 2024 RDX should be fully covered under Acura's warranty. Out-of-warranty reference costs:
- Boost leak repair: $150–$400
- MAF sensor cleaning: $15–$40 (DIY)
- MAF sensor replacement: $180–$350
- High-pressure fuel pump: $500–$900
- Intake manifold gasket: $250–$500
Should You Drive With P0174?
For a 2024 model, schedule a warranty appointment as soon as possible. Running lean on a turbocharged engine risks engine knock under boost, which can damage pistons and the head gasket. Avoid spirited driving and towing until the issue is resolved. Light city driving is acceptable in the interim.
Warranty Coverage
The 2024 RDX is covered by Acura's 4-year/50,000-mile basic warranty and 6-year/70,000-mile powertrain warranty. Any defective component causing P0174 — whether a sensor, gasket, or fuel system part — should be repaired at no charge at your Acura dealer. Do not attempt DIY repairs that could affect warranty coverage on a vehicle this new.