What P0171 Means on Your 2022 Acura TLX
A P0171 code on your 2022 Acura TLX indicates the engine control module detected a lean air-fuel mixture on Bank 1. The 2022 TLX uses a 2.0L turbocharged four-cylinder (K20C6) producing 272 horsepower, while the TLX Type S features a 3.0L twin-turbo V6 (J30A) with 355 horsepower. On the inline-four, Bank 1 covers all cylinders. On the V6, Bank 1 is the rear bank. A lean condition means excess air or insufficient fuel.
The TLX is Acura's performance sedan, and precise air-fuel control is critical for both refinement and performance. Here is how to handle P0171.
Symptoms
- Check engine light on
- Rough or unsteady idle
- Hesitation or turbo lag during acceleration
- Decreased fuel economy
- Possible reduced boost pressure
- Less smooth power delivery
Common Causes
- Boost Leak (35% likelihood) - Both the 2.0L turbo and 3.0L twin-turbo have extensive charge piping. A loose clamp, cracked pipe, or leaking intercooler connection lets pressurized air bypass the MAF sensor.
- MAF Sensor Issue (25% likelihood) - Contamination from PCV oil mist or aftermarket air filters can affect MAF accuracy on either engine.
- Fuel Delivery Problem (20% likelihood) - The direct injection system requires consistent high fuel pressure. A weak pump or clogged injector creates lean conditions.
- PCV System Issue (20% likelihood) - A stuck or failed PCV valve introduces excess crankcase air into the intake.
Diagnostic Steps
- Full code scan. Check for boost, misfire, or fuel system codes.
- Fuel trim monitoring. LTFT above +10% confirms lean. Check under boost conditions.
- Turbo plumbing inspection. Check all charge pipes, intercooler hoses, and clamps.
- MAF sensor cleaning. Use dedicated MAF cleaner.
- PCV valve check. Verify proper operation.
- Fuel pressure test. Verify high-pressure rail readings.
Repair Costs
- Boost pipe or clamp repair: $75 - $350.
- MAF sensor service: $15 - $320.
- PCV valve replacement: $50 - $200.
- High-pressure fuel pump: $450 - $1,000.
Warranty Check
The 2022 TLX has a 4-year/50,000-mile basic warranty and 6-year/70,000-mile powertrain warranty. Verify your coverage.
Prevention Tips
- Use OEM air filters
- Fill up with premium fuel as required
- Inspect turbo hoses during routine service
- Follow the factory maintenance schedule
- Address check engine lights promptly