What Does P0171 Mean on Your 2022 Buick Enclave?
If your 2022 Buick Enclave has triggered a P0171 code, the powertrain control module (PCM) has detected that Bank 1 of the engine is running too lean. The 2022 Enclave is powered by GM's 3.6-liter V6 engine (LGX) producing 310 horsepower. Bank 1 is typically the rear cylinder bank (cylinders 2, 4, 6) on this transverse-mounted V6. The PCM is seeing that it has to add more fuel than normal to maintain the correct air-fuel ratio.
Symptoms You Might Notice
- Check engine light on
- Rough or uneven idle
- Hesitation when accelerating from a stop
- Reduced fuel economy from the typical 18-26 MPG range
- Engine may feel like it's struggling under load
- Occasional stumble or misfire sensation
Common Causes of P0171 on the 2022 Buick Enclave
GM's 3.6L V6 has some well-documented lean condition triggers:
- Vacuum Leak (35% likelihood) — Check the intake manifold gaskets, PCV valve and hoses, and brake booster vacuum line. The intake gaskets on GM V6 engines are a known weak point.
- MAF Sensor Issue (25% likelihood) — A dirty or failing mass air flow sensor will cause incorrect airflow calculations, leading to lean fuel trims.
- Fuel Pump Weakness (25% likelihood) — The in-tank fuel pump may be losing pressure, especially under load. GM's fuel pump modules can wear out over time.
- Exhaust Leak Before O2 Sensor (15% likelihood) — A small exhaust leak near the manifold or upstream O2 sensor can introduce fresh air, fooling the sensor into reporting a lean condition.
How to Diagnose the Problem
- Scan for all codes — Use a quality OBD-II scanner to check for additional codes. Look for P0174 (Bank 2 lean) which would indicate a system-wide issue.
- Check fuel trims — Monitor STFT and LTFT on both banks. If only Bank 1 is elevated, the problem is bank-specific (vacuum leak, exhaust leak). If both banks are lean, suspect MAF or fuel delivery.
- Inspect for vacuum leaks — Check all vacuum hoses, the PCV system, and the intake manifold gaskets. A smoke test is the most effective method.
- Test fuel pressure — Key-on fuel pressure should be around 55-62 PSI. Low pressure indicates a weak fuel pump or clogged filter.
- Inspect exhaust connections — Look for cracks or loose bolts at the exhaust manifold and the connection to the catalytic converter.
Repair Options and Cost Breakdown
- Vacuum leak repair: $100–$350. DIY cost is $15–$60. Intake gaskets are affordable but require some labor to access.
- MAF sensor replacement: $150–$300. Parts run $50–$120. Very easy DIY — unplug and swap in 10 minutes.
- Fuel pump replacement: $400–$800. Parts cost $200–$400. Requires dropping the fuel tank, which is doable with a lift and proper safety precautions.
- Exhaust manifold gasket repair: $200–$500. Parts are cheap ($20–$50), but labor on the rear bank can be significant.
Prevention Tips
- Use quality fuel from reputable stations
- Replace the engine air filter every 15,000–20,000 miles
- Don't ignore small performance changes — they often indicate developing issues
- Follow GM's recommended maintenance schedule for the 3.6L engine
- Have the PCV system inspected during oil changes
Is It Safe to Drive?
Your Enclave is generally safe to drive with a P0171 code for short trips around town. However, the Enclave is a three-row family vehicle that's often fully loaded, and running lean under heavy load can stress the catalytic converters. Get it checked out within a week or two.