What P0174 Means on the 2024 Acura TLX
The 2024 Acura TLX continues with two turbocharged engine options: the 2.0L turbo four-cylinder (K20C4, 272 hp) and the Type S 3.0L twin-turbo V6 (J30A, 355 hp). P0174 signals that the engine is running lean on Bank 2 — the PCM has detected excess air or insufficient fuel in the combustion mixture. On the Type S V6, this affects a specific cylinder bank. On the 2.0T, it represents a generalized lean condition since inline-fours have one bank.
Common Symptoms
- Check engine light illuminated
- Rough or inconsistent idle quality
- Hesitation or lag during acceleration
- Reduced boost pressure feel
- Drop in fuel economy
Root Causes on the 2024 TLX
1. Charge Air System Leaks
Both TLX engines are turbocharged, and the pressurized charge air system is the first place to investigate. On the 2.0T, check intercooler hose connections and the charge pipe to throttle body joint. On the Type S, the twin-turbo setup doubles the potential leak points with dual charge pipes, an air-to-water intercooler, and recirculation valves. Even on a new vehicle, a factory assembly oversight like an undertorqued clamp can create a leak.
2. MAF Sensor Issues
The MAF sensor on both TLX variants sits upstream of the turbocharger in the air intake duct. Factory oil residue in the intake or an aftermarket air filter can contaminate the sensing element early in the vehicle's life. A contaminated MAF underestimates airflow, causing the PCM to lean out fuel delivery.
3. Direct Injection Fuel Delivery
The K20C4 and J30A both use high-pressure direct fuel injection. A fuel injector with an abnormal spray pattern or a high-pressure pump not reaching target pressure will create lean combustion. On a 2024 model, this is most likely a manufacturing defect rather than wear.
4. PCV System Fault
Turbocharged engines produce significant crankcase pressure. The PCV system routes blow-by gases back into the intake. A stuck PCV valve or disconnected hose can allow unmetered air into the intake manifold, triggering a lean code. Inspect the PCV routing and valve operation.
How to Diagnose
- Pull all DTCs and review freeze frame data
- Check long-term fuel trims — values above +10% confirm the lean condition
- Boost leak test the charge air system
- Inspect all turbo piping connections and clamps
- Clean and test the MAF sensor
- Monitor fuel rail pressure under various conditions
Repair Cost Estimates
The 2024 TLX should be under full warranty coverage:
- Boost leak repair: $150–$450
- MAF sensor cleaning: $25–$40 (DIY)
- MAF sensor replacement: $180–$380
- Fuel pump replacement: $550–$1,000
- PCV valve replacement: $80–$200
Is It Safe to Drive?
Running lean on either turbocharged TLX engine is risky under boost. Lean mixtures cause elevated combustion temperatures and can lead to detonation. For a 2024 model, contact your Acura dealer immediately. Avoid aggressive driving until the issue is resolved. Light city driving at moderate throttle is acceptable in the interim.
Warranty and Service Advice
The 2024 TLX is covered by Acura's 4-year/50,000-mile basic warranty and 6-year/70,000-mile powertrain warranty. P0174-related repairs should be handled at no cost by your Acura dealer. Do not perform DIY repairs beyond basic inspection on a vehicle this new — let the dealer diagnose and fix it under warranty to protect your coverage.