Understanding P0174 on the 2024 Buick Envision
The 2024 Buick Envision continues with the 2.0L turbocharged four-cylinder (LSY) producing 228 horsepower. P0174 means the PCM detected a lean condition — excess air or insufficient fuel in the combustion mixture. On this inline-four engine, the code indicates a generalized lean state where long-term fuel trims have exceeded normal parameters.
Common Symptoms
- Check engine light illuminated
- Slight idle roughness
- Acceleration hesitation
- Reduced boost response
- Lower fuel economy
Causes on the 2024 Envision
1. Charge Air System Leak
The LSY turbo system can have a factory assembly defect — an undertorqued clamp, misaligned coupler, or defective diverter valve. Even on a brand-new vehicle, boost leaks are the most common cause of lean codes on turbocharged engines. A boost leak test at 15-20 psi quickly identifies the source.
2. MAF Sensor Contamination
Factory assembly residue in the intake tract or early PCV contamination can affect the MAF sensor. Underreading airflow causes lean fueling. Clean with MAF-specific spray as a first step.
3. Fuel System Defect
A manufacturing defect in the high-pressure pump or a fuel injector with an abnormal spray pattern can starve the engine of fuel. This is uncommon but possible on new vehicles.
4. PCV or Intake Gasket Issue
A factory assembly defect in the PCV system or intake manifold gasket can introduce unmetered air. Smoke testing reveals these problems.
Diagnostic Steps
- Full DTC scan with freeze frame review
- Check fuel trim values for both short-term and long-term
- Boost leak test on charge air system
- Inspect charge piping and diverter valve
- Clean and test MAF sensor
- Monitor fuel pressure under load
Repair Costs
Under Buick's warranty, repairs are free. Reference costs:
- Boost leak repair: $100–$350
- MAF sensor cleaning: $15–$35 (DIY)
- MAF sensor replacement: $130–$280
- Fuel pump: $400–$700
- PCV/gasket repair: $60–$200
Should You Drive With P0174?
Light driving is acceptable short-term. Avoid hard acceleration and heavy loads on the turbocharged engine. For a 2024 model, schedule a warranty appointment promptly. Buick's 4-year/50,000-mile warranty covers manufacturing defects.
Warranty Coverage
The 2024 Envision has Buick's 4-year/50,000-mile bumper-to-bumper warranty and 6-year/70,000-mile powertrain warranty. All defective component repairs causing P0174 should be handled at no charge by your Buick dealer. Avoid DIY repairs beyond basic inspection on a vehicle under warranty.