2023 Acura P0171: What It Means & Is It Safe to Drive?
P0171 on the 2023 Acura: System Too Lean (Bank 1). Here's what it means, what usually causes it, what repairs typically cost, and whether it's safe to keep driving.
What this code means
The engine is getting too much air relative to fuel. The O2 sensor sees excess oxygen in the exhaust and the PCM is adding more fuel than normal to compensate.
Common causes on the 2023 Acura
- Dirty or faulty mass airflow (MAF) sensor
- Vacuum leaks (PCV hose, intake gasket, brake booster)
- Weak fuel pump or clogged fuel filter
- Leaking or stuck open fuel injectors (less common)
Symptoms
- Check Engine Light
- Rough idle, hesitation, lack of power
- Possible spark knock under load
- Poor fuel economy
Typical fixes
- Clean or replace MAF sensor
- Locate and seal vacuum leaks
- Replace fuel filter / test fuel pressure
- Smoke test intake system
Repair cost range
For a 2023 Acura, repairs for P0171 typically fall between $50 and $500, depending on the root cause and labor rates in your area.
Known issues on Acura
Acura P0171 on J35 V6 (MDX, Pilot, TL) shares Honda's lean diagnosis approach—focus on vacuum leaks before MAF. The IAC (Idle Air Control) valve passage clogs with carbon on J-series engines, causing lean conditions at idle. On RDX 2.3T K23A1 turbo, the turbo inlet pipe couplers crack and admit unmetered air after the MAF—this is the most common P0171 cause. On TL with VTEC, ensure the VTEC oil pressure solenoid passages are clear; a partial solenoid blockage can alter cam lift and affect air metering.
Most commonly affected models