What P0174 Means for Your 2024 Acura MDX
The 2024 Acura MDX continues with its proven 3.5L V6 (J35Y6) producing 290 horsepower in the standard model, or the 3.0L turbocharged V6 (J30A) making 355 horsepower in the Type S. A P0174 code indicates that Bank 2 is running lean — the PCM has detected that the air-fuel mixture has too much air or insufficient fuel on the rear cylinder bank. The system's long-term fuel trims have exceeded the normal adjustment window.
Symptoms to Expect
- Check engine light on
- Slight rough or inconsistent idle
- Mild hesitation during acceleration from stops
- Reduced fuel economy
- On the Type S turbo, possible reduced boost or power delivery
Primary Causes on the 2024 MDX
1. Vacuum or Boost Leaks
On the standard 3.5L MDX, inspect the intake manifold gaskets, PCV hose, and brake booster vacuum line for leaks. On the Type S with the turbocharged 3.0L, boost leaks from intercooler piping, charge air connections, or wastegate actuator vacuum lines are more likely culprits. Even on a new vehicle, a factory clamp not fully tightened or a gasket with a manufacturing defect can cause a leak. Smoke testing or boost pressure testing is the definitive diagnostic method.
2. MAF Sensor Issues
The mass airflow sensor measures incoming air and sends data to the PCM for fuel calculations. Contamination from oil vapor, dust, or an improperly installed aftermarket filter can cause inaccurate readings. The MAF underreporting airflow leads to insufficient fuel injection. On a 2024 model, this could stem from aftermarket modifications or factory assembly residue.
3. Fuel Delivery Problems
The standard J35Y6 uses port fuel injection, while the Type S J30A uses direct injection. On either engine, a weak fuel pump, failing pressure regulator, or restricted injector can prevent adequate fuel delivery to Bank 2. The Type S's high-pressure direct injection system operates at significantly higher pressures and requires professional diagnostic equipment to evaluate properly.
4. O2 Sensor or Wiring Issue
A faulty upstream oxygen sensor on Bank 2 can send incorrect readings to the PCM, making it adjust fueling incorrectly. Wiring damage from road debris or rodent activity can also affect sensor signals. On a new vehicle, check for TSBs (Technical Service Bulletins) related to sensor calibration or wiring routing.
Diagnostic Steps
- Read all DTCs and check for related codes like P0171, misfire codes, or boost codes
- Check freeze frame data and long-term fuel trim values for Bank 2
- Perform a smoke test (standard MDX) or boost leak test (Type S)
- Inspect and clean the MAF sensor
- Test fuel pressure at the fuel rail
- Monitor Bank 2 upstream O2 sensor live data
Repair Cost Estimates
The 2024 MDX should be under Acura's 4-year/50,000-mile warranty. Out-of-warranty estimates:
- Vacuum or boost leak repair: $150–$450
- MAF sensor cleaning: $25–$45 (DIY)
- MAF sensor replacement: $180–$380
- Fuel pump replacement: $450–$800
- O2 sensor replacement: $200–$400
Safe to Drive?
Light driving is acceptable short-term. On the Type S turbo model, avoid aggressive acceleration as lean mixtures under boost can cause detonation. On the standard V6, the risk is primarily to the catalytic converter over time. Schedule a warranty appointment promptly — Acura should handle this at no charge on a 2024 model.
Warranty vs. DIY
For a 2024 MDX, the warranty is your best resource. Do not attempt repairs that could void coverage. If you want to investigate, MAF sensor cleaning and visual inspection of hoses are non-invasive checks that will not affect warranty status. For any component replacement, let the dealer handle it under warranty.