P0171 on Your 2024 Acura MDX
A P0171 code on your 2024 Acura MDX means the ECM detected a lean air-fuel mixture on Bank 1. The 2024 MDX uses a 3.5L V6 producing 290 horsepower, while the Type S has a 3.0L twin-turbo V6 with 355 horsepower. A lean condition means the air-fuel ratio on Bank 1 has too much air or too little fuel.
As a 2024 model, your MDX is under Acura's factory warranty. Here is what to know.
Symptoms
- Check engine light on
- Rough or uneven idle
- Hesitation during acceleration
- Fuel economy below expectations
- Possible reduced turbo response (Type S)
- Engine less smooth than normal
Common Causes
- Vacuum or Boost Leak (30% likelihood) - Factory assembly issues can leave hoses loose. The Type S turbo plumbing adds more potential leak points.
- MAF Sensor Issue (30% likelihood) - A defective or contaminated MAF sensor can misread airflow.
- Fuel System Defect (20% likelihood) - A defective injector or fuel pressure issue can cause lean conditions.
- ECM Calibration (20% likelihood) - Honda/Acura may have a software update for the 2024 MDX that addresses fuel trim behavior.
Diagnostic Steps
- Dealer TSB check. Have the dealer check for bulletins.
- Fuel trim monitoring. LTFT above +10% confirms lean.
- Intake inspection. Check all connections and hoses.
- MAF sensor evaluation. Compare to factory specs.
- Software update check. An ECM reflash may be available.
Repair Costs
- Under warranty: $0. Covered by Acura's factory warranty.
- Vacuum leak repair (out of warranty): $100 - $400.
- MAF sensor (out of warranty): $200 - $350.
- Fuel injector (out of warranty): $300 - $800.
- ECM reflash (out of warranty): $100 - $200.
Acura Warranty
The 2024 MDX has a 4-year/50,000-mile basic warranty and 6-year/70,000-mile powertrain warranty. P0171 is covered. Visit your authorized Acura dealer for no-cost repair.
Prevention Tips
- Use OEM air filters
- Fill up with premium fuel
- Avoid aftermarket intake modifications
- Respond promptly to check engine lights
- Follow the factory maintenance schedule