What P0174 Means on the 2024 Buick Encore GX
The 2024 Buick Encore GX uses a 1.2L turbocharged three-cylinder engine (L8B) producing 137 horsepower, or the available 1.3L turbo three-cylinder (L3T) with 155 horsepower. P0174 indicates a lean condition — the PCM has detected excess air or insufficient fuel in the combustion mixture. On these inline-three engines, the code represents a generalized lean state.
Symptoms
- Check engine light on
- Rough idle or increased vibration
- Acceleration hesitation
- Reduced boost feel
- Lower fuel economy
Causes on the 2024 Encore GX
1. Boost System Leak
The compact turbo system can have factory assembly issues on charge pipe connections. A loose hose clamp, unseated coupler, or defective diverter valve allows boost pressure to escape. On a three-cylinder engine, even a small leak significantly affects the air-fuel ratio due to the lower overall airflow volume.
2. MAF Sensor Issue
Factory residue or early PCV contamination can affect the MAF sensor on a new vehicle. The three-cylinder engine's lower airflow volume means MAF inaccuracies have a proportionally larger impact on fuel delivery.
3. Fuel Delivery Deficiency
A manufacturing defect in the high-pressure pump or a direct fuel injector can cause lean fueling from the start. Three-cylinder engines rely heavily on each injector — one underperforming injector represents 33% of total fuel delivery.
4. PCV or Intake Gasket Leak
A PCV valve defect or improperly seated intake manifold gasket from the factory can introduce unmetered air. Smoke testing reveals these issues.
Diagnostic Steps
- Scan for all DTCs and freeze frame data
- Check fuel trim values — above +10% confirms lean condition
- Boost leak test at 10-15 psi
- Inspect charge piping connections
- Clean and test MAF sensor
- Monitor fuel pressure under various conditions
Repair Costs
Under warranty, repairs are free. Reference costs:
- Boost leak repair: $100–$300
- MAF sensor cleaning: $15–$30 (DIY)
- MAF sensor replacement: $120–$250
- Fuel pump: $350–$650
- PCV/gasket repair: $80–$200
Safe to Drive?
Light driving is okay temporarily. The small three-cylinder turbo is sensitive to lean conditions — avoid hard acceleration and let the dealer handle it under Buick's 4-year/50,000-mile warranty.
Warranty Info
The 2024 Encore GX has a 4-year/50,000-mile bumper-to-bumper warranty and 6-year/70,000-mile powertrain warranty. All P0174-related defect repairs should be covered at no charge at your Buick dealer.