P0174 on the 2022 Acura TLX: What Is Going On
The 2022 Acura TLX is available with two turbocharged engines: the standard 2.0L turbo four-cylinder (K20C4, 272 hp) and the Type S with a 3.0L twin-turbo V6 (J30A, 355 hp). P0174 indicates a lean condition on Bank 2. On the four-cylinder TLX, this represents a generalized lean state since inline-fours have a single bank. On the Type S V6, Bank 2 is a specific cylinder bank that is running lean relative to the ECM's targets.
Symptoms You May Experience
- Check engine light on
- Rough or hunting idle
- Reduced power or hesitation under acceleration
- Diminished turbo boost response
- Noticeable decrease in fuel economy
Common Causes for the 2022 TLX
1. Boost System Leaks
Both TLX engines are turbocharged, making boost leaks the primary suspect for P0174. On the 2.0T, check the intercooler piping, charge pipe connections, and bypass valve. On the Type S 3.0T, the twin-turbo setup has even more potential leak points including dual charge pipes, intercooler connections, and recirculation valves. A boost leak test is essential — apply 15-20 psi of regulated air through the intake and listen or use soapy water to find escaping air.
2. MAF Sensor Contamination
The hot-wire MAF sensor sits in the intake duct upstream of the turbocharger(s). Oil mist from the PCV system, which is significant on turbocharged engines due to higher crankcase pressures, can coat the sensor element. A contaminated MAF underreads airflow, causing lean fueling. This is a quick, inexpensive check — remove and clean with MAF-specific spray.
3. Fuel System Weakness
Both TLX engines use direct fuel injection with high-pressure pumps. The Type S 3.0T twin-turbo has an even more demanding fuel system. A failing high-pressure pump, weak in-tank low-pressure pump, or restricted injectors will result in insufficient fuel delivery under load. Monitor fuel pressure live data through a diagnostic scan tool.
4. Intake Manifold or Gasket Leak
An air leak at the intake manifold-to-head gasket allows unmetered air into the combustion chambers. On the Type S V6, a Bank 2-specific gasket leak could cause P0174 without triggering P0171 on Bank 1. Smoke testing is the definitive diagnostic for intake manifold leaks.
Diagnostic Procedure
- Scan for all DTCs — check for P0171, boost codes, and misfire codes
- Review freeze frame data for fuel trim values and engine operating conditions
- Perform a boost leak test on the charge air system
- Inspect all turbo piping, intercooler connections, and clamps
- Clean and evaluate the MAF sensor
- Test fuel rail pressure at idle and under boost using a scan tool
Repair Costs for the 2022 Acura TLX
- Boost leak repair: $150–$450
- MAF sensor cleaning: $25–$40 (DIY)
- MAF sensor replacement: $180–$380
- High-pressure fuel pump: $550–$950
- Intake manifold gasket: $250–$500
Note: Type S repairs generally cost 15-25% more due to the more complex twin-turbo V6 architecture and higher OEM parts pricing.
Can You Drive With P0174?
Both TLX engines are turbocharged, making a lean condition potentially dangerous under boost. Lean mixtures combined with boost pressure create conditions for engine knock, which can damage pistons, rings, and bearings. Avoid spirited driving and stay out of boost as much as possible until diagnosed. The 2022 model may still be under Acura's warranty — check your coverage.
DIY Feasibility
MAF sensor cleaning and boost piping inspection are accessible DIY tasks on the 2.0T TLX. The Type S 3.0T has a more crowded engine bay, making access to some components challenging. For fuel system diagnostics on either engine, professional equipment is recommended. If under warranty, the dealer is the most efficient path to resolution.