What Does P0171 Mean on Your 2022 Buick Encore GX?
A P0171 code on your 2022 Buick Encore GX indicates that Bank 1 is running too lean — too much air or not enough fuel in the combustion mixture. The 2022 Encore GX is available with either a 1.2-liter turbocharged three-cylinder (137 hp) or a 1.3-liter turbocharged three-cylinder (155 hp). Since both are inline engines, there's only one bank. The engine control module is adding extra fuel to compensate for the lean condition.
Symptoms You Might Notice
- Check engine light illuminated
- Rough idle, especially noticeable in a small three-cylinder engine
- Hesitation or stumbling on acceleration
- Reduced fuel economy below the usual 29-32 MPG
- Engine feels weak or underpowered, particularly on inclines
- Occasional stalling at idle in severe cases
Common Causes of P0171 on the 2022 Buick Encore GX
The small-displacement turbo engines in the Encore GX are particularly sensitive to air-fuel ratio imbalances:
- Vacuum or Boost Leak (35% likelihood) — The turbo charge pipes, intercooler connections, and intake manifold gasket are common leak points. Even a small leak is significant on these small engines.
- MAF Sensor Contamination (30% likelihood) — The mass air flow sensor in these compact engines can get dirty quickly, especially in dusty conditions or with oil seepage from the PCV system.
- Fuel Injector Issue (20% likelihood) — A partially clogged or leaking fuel injector can disrupt the precise fuel delivery these small turbocharged engines require.
- PCV Valve Failure (15% likelihood) — A stuck or failed PCV valve can cause vacuum leaks and disrupt the crankcase ventilation system.
How to Diagnose the Problem
- Scan for codes — Use an OBD-II scanner to read all stored and pending codes. Check for misfire codes that may accompany P0171.
- Check fuel trims — Monitor STFT and LTFT. Values above +10-15% confirm a lean condition. On three-cylinder engines, lean conditions are more pronounced.
- Visual inspection — Check all vacuum hoses, the turbo inlet pipe, charge pipe clamps, and intercooler connections for loose fits or cracks.
- Smoke test — The most reliable way to find leaks in the compact engine bay of the Encore GX.
- Test fuel pressure — Monitor fuel rail pressure at idle and under load to rule out fuel delivery problems.
Repair Options and Cost Breakdown
- Vacuum or boost leak repair: $80–$250. DIY cost is $10–$50. These small engines have simpler plumbing that's easier to work on.
- MAF sensor replacement: $100–$220. Parts run $40–$90. Very easy 10-minute DIY job.
- Fuel injector service: $200–$450. Professional cleaning is $80–$150. Full replacement is $300–$500 for all three injectors.
- PCV valve replacement: $80–$180. Part cost is $15–$40. Usually accessible and easy to replace.
Prevention Tips
- Use quality fuel — Top Tier gasoline helps keep injectors clean
- Replace the air filter every 15,000 miles or sooner in dusty conditions
- Don't skip oil changes — clean oil protects the PCV system and turbo
- Listen for unusual boost or intake noises that could signal developing leaks
- Follow GM's maintenance schedule for the turbocharged engine
Is It Safe to Drive?
You can safely drive your Encore GX with P0171 for short trips, but these small turbo engines are less tolerant of lean conditions than larger engines. The turbocharger runs hotter when the mixture is lean, and extended lean operation can shorten turbo life. Get it diagnosed within a week.