What Does P0171 Mean on Your 2024 Buick Encore GX?
When your 2024 Buick Encore GX triggers a P0171 code, the engine control module is reporting a lean air-fuel mixture. The 2024 Encore GX comes with a 1.2-liter turbocharged three-cylinder engine producing 137 horsepower. As an inline engine, there's only one bank, so P0171 applies to the entire engine. The ECM has detected that it's adding more fuel than expected to maintain the proper combustion ratio.
Symptoms You Might Notice
- Check engine light on
- Noticeably rough idle — more apparent in a three-cylinder engine
- Sluggish acceleration, especially from stops
- Fuel economy dropping below the expected 30-33 MPG
- Engine vibration at low speeds or idle
- Occasional hesitation when merging onto highways
Common Causes of P0171 on the 2024 Buick Encore GX
Since this is a new vehicle, warranty coverage should apply to most fixes:
- Boost or Intake Leak (30% likelihood) — Factory assembly issues with charge pipes, clamps, or gaskets that allow unmetered air into the system.
- ECM Software Calibration (30% likelihood) — First-year or early-production software may need fuel trim calibration updates from GM.
- MAF Sensor Issue (25% likelihood) — A defective or contaminated mass air flow sensor providing incorrect readings to the ECM.
- Fuel System Component (15% likelihood) — A weak fuel pump, faulty fuel pressure sensor, or problematic injector.
How to Diagnose the Problem
- Go to your Buick dealer — The 2024 Encore GX is covered by GM's 3-year/36,000-mile bumper-to-bumper and 5-year/60,000-mile powertrain warranty.
- Request TSB lookup — Ask the dealer to check for Technical Service Bulletins specific to the 1.2T engine and P0171.
- If diagnosing independently — Check fuel trims with an OBD-II scanner. Positive LTFT above 10% confirms the lean condition.
- Smoke test — Identifies hidden vacuum or boost leaks efficiently.
- Check for intake noise — A hissing or whistling sound under the hood can indicate a boost leak.
Repair Options and Cost Breakdown
- Boost or intake leak repair: $80–$250. Should be free under warranty.
- ECM software update: $0–$150. Covered under warranty or TSB at the dealer.
- MAF sensor replacement: $100–$200. Part cost is $40–$80. Simple DIY if out of warranty.
- Fuel system repair: $300–$700. Covered under powertrain warranty.
Prevention Tips
- Use quality fuel from reputable stations
- Keep up with scheduled dealer maintenance
- Report any unusual engine behavior to the dealer promptly
- Use GM-recommended oil and filters
- Avoid aftermarket intake modifications on a warrantied vehicle
Warranty Information
Your 2024 Buick Encore GX is fully covered under GM's warranty program. The 3-year/36,000-mile bumper-to-bumper warranty covers all engine-related components, and the 5-year/60,000-mile powertrain warranty adds additional protection. Take the vehicle to an authorized Buick dealer for free diagnosis and repair.