P0174 on the 2022 Buick Enclave: What It Means
The 2022 Buick Enclave is powered by a 3.6L naturally aspirated V6 engine (LFY/LGX) producing 310 horsepower, paired with a 9-speed automatic transmission. P0174 indicates that Bank 2 of the V6 is running lean — the powertrain control module has detected that the air-fuel mixture has too much air or insufficient fuel. On the GM 3.6L V6, Bank 2 is the rear cylinder bank closest to the firewall. Long-term fuel trims have exceeded the normal +/-10% range.
Symptoms You May Notice
- Check engine light on
- Rough or slightly unstable idle
- Hesitation or stumble during gentle acceleration
- Marginal decrease in fuel economy
- Possible idle surging
Common Causes on the GM 3.6L V6
1. Intake Manifold Gasket Leak
The GM 3.6L V6 in the Enclave uses a composite intake manifold with rubber O-ring gaskets. These gaskets are a known failure point on GM 3.6L engines and can shrink or harden over time, allowing unmetered air into the combustion chambers. Bank 2-specific lean codes often point to gaskets on the rear bank, which are harder to inspect visually. A smoke test of the intake system is the most effective diagnostic method.
2. MAF Sensor Contamination
The mass airflow sensor on the Enclave sits in the air intake duct between the air filter box and throttle body. Oil vapor from the PCV system or a dirty air filter can contaminate the hot-wire sensing element. The sensor then underreports airflow, causing the PCM to inject too little fuel. Cleaning with MAF sensor cleaner spray is a quick, inexpensive first step.
3. Fuel Delivery Issues
The LFY/LGX engine uses direct injection with a high-pressure fuel pump. The GM high-pressure pump on this engine is generally reliable, but a failing pump, clogged fuel filter, or carbon-fouled injectors can reduce fuel delivery. Carbon buildup on the intake valves is a known issue with direct injection engines that can indirectly contribute to lean conditions by affecting airflow patterns.
4. Vacuum Line Deterioration
Various vacuum lines in the Enclave's engine bay service the brake booster, EVAP system, PCV system, and other components. Heat cycling causes rubber vacuum lines to crack and split over time. A cracked vacuum hose allows air to bypass the MAF sensor. Visually inspect all vacuum connections, especially those routed near hot exhaust components.
Diagnostic Approach
- Scan for all DTCs — check for P0171 alongside P0174
- Review freeze frame data for long-term fuel trim values on both banks
- Perform a smoke test on the intake manifold and vacuum system
- Clean and test the MAF sensor
- Test fuel pressure at the fuel rail at idle and under snap acceleration
- Inspect intake valve condition if mileage is over 80,000
Repair Cost Estimates for the 2022 Enclave
Buick parts are priced moderately — less than European luxury but slightly above mainstream GM brands:
- Intake manifold gasket replacement: $250–$500
- MAF sensor cleaning: $20–$40 (DIY)
- MAF sensor replacement: $150–$300
- Fuel pump replacement: $400–$750
- Vacuum hose repair: $50–$150
Can You Drive With P0174?
The naturally aspirated 3.6L V6 is more tolerant of mild lean conditions than turbocharged engines. You can drive the Enclave for normal errands without immediate risk. However, extended lean operation can overheat the Bank 2 catalytic converter, which is an expensive replacement ($800+). Address the issue within 2-3 weeks.
DIY Feasibility
The Enclave's engine bay provides reasonable access for DIY work. MAF sensor cleaning takes 10 minutes. Vacuum line inspection is visual and tactile. Intake manifold gasket replacement is a moderate DIY project — the upper intake manifold must be removed, which requires careful disconnection of wiring and hoses but is well-documented in GM service manuals and forums.