Understanding P0174 on the 2024 Buick Enclave
The 2024 Buick Enclave continues with the proven 3.6L naturally aspirated V6 (LFY) producing 310 horsepower, paired with a 9-speed automatic transmission. P0174 means Bank 2 of the V6 is running lean — the PCM has detected that the rear cylinder bank has too much air or insufficient fuel in the air-fuel mixture. Long-term fuel trims have exceeded the normal correction range.
Symptoms to Expect
- Check engine light illuminated
- Slightly rough idle
- Hesitation during gentle acceleration
- Marginal drop in fuel economy
- Possible occasional misfire sensation at idle
Root Causes on the 2024 Enclave
1. Intake Manifold Gasket Leak
The GM 3.6L V6 is known for intake manifold gasket issues. The composite intake manifold uses rubber O-ring gaskets that seal against the cylinder heads. On a 2024 model, a manufacturing defect in the gasket material or improper seating during assembly could cause a leak. A smoke test of the intake system quickly identifies this problem.
2. MAF Sensor Contamination
The MAF sensor can be affected by factory assembly residue or PCV oil vapor migration early in the vehicle's life. Underreading airflow causes the PCM to deliver insufficient fuel. Clean with MAF-specific spray before considering replacement.
3. Fuel System Issue
The direct injection system on the 3.6L uses a high-pressure fuel pump and six individual injectors. A defective injector on Bank 2 or a weak pump can cause lean fueling. On a new vehicle, this would be a manufacturing defect covered under warranty.
4. Vacuum Line Manufacturing Defect
A vacuum line that was improperly routed, kinked, or not fully connected during factory assembly can create an air leak. Check all vacuum connections on the rear side of the engine.
Diagnostic Steps
- Scan for all DTCs and review freeze frame data
- Check long-term fuel trim values for both banks
- Perform an intake smoke test
- Clean and test the MAF sensor
- Test fuel pressure at idle and under load
- Check for GM TSBs related to P0174 on 2024 Enclave
Repair Cost Estimates
The 2024 Enclave should be under GM's warranty. Reference costs:
- Intake manifold gasket: $250–$500
- MAF sensor cleaning: $20–$40 (DIY)
- MAF sensor replacement: $150–$300
- Fuel pump: $400–$750
- Vacuum line repair: $50–$150
Is It Safe to Drive?
The naturally aspirated 3.6L V6 is forgiving of mild lean conditions. You can drive normally for daily errands, but have it checked under warranty within a couple of weeks. Extended lean operation can damage the catalytic converter over time.
Warranty Coverage
The 2024 Enclave is covered by Buick's 4-year/50,000-mile bumper-to-bumper warranty and 6-year/70,000-mile powertrain warranty. Manufacturing defects causing P0174 are covered at no charge. Take it to your Buick dealer for diagnosis and repair.