What Does P0172 Mean on Your 2024 Buick Enclave?
A P0172 code on your 2024 Buick Enclave indicates the engine control module has detected that Bank 1 is running richer than the ideal air-fuel ratio. The 2024 Enclave uses a 3.6-liter naturally aspirated V6 producing 310 horsepower with a 9-speed automatic transmission. Bank 1 is the cylinder bank that includes cylinder number 1.
Running rich means there is too much fuel in the combustion mixture relative to the air. This reduces fuel economy, increases emissions, and can cause damage to engine components over time if not corrected.
Symptoms You May Notice
- Check engine light on
- Worse fuel economy than the rated 18/26 mpg
- Rough or uneven idle
- Dark or black exhaust smoke
- Gasoline smell from the exhaust
- Sluggish acceleration
- Potential misfires on Bank 1 cylinders
Common Causes of P0172 on the 2024 Buick Enclave
- Contaminated MAF Sensor - The mass airflow sensor is the top cause. Debris and oil film reduce its accuracy, causing the ECM to add too much fuel.
- EVAP Purge Valve Stuck Open - A common GM issue where the purge valve fails to close, allowing continuous fuel vapor flow into the intake manifold.
- Leaking Fuel Injector - Direct injection injectors on the 3.6L V6 can develop leaks at high operating pressures.
- Failing Bank 1 Upstream O2 Sensor - A degraded oxygen sensor sends inaccurate data that causes the ECM to over-fuel.
How to Diagnose P0172
- Read all codes - Check for EVAP, MAF, O2, or misfire companion codes.
- Check fuel trim data - Negative LTFT on Bank 1 beyond -10% confirms the issue.
- Clean and inspect the MAF - Always the cheapest first step.
- Test the EVAP purge valve - Apply vacuum and verify the valve holds and releases properly.
- Monitor O2 sensors - Watch Bank 1 upstream sensor for slow or stuck readings.
- Test fuel injectors - Check for proper operation and sealing on Bank 1 injectors.
Repair Options and Cost Breakdown
- MAF Sensor Cleaning - $12-$25 for spray. Easy DIY.
- MAF Sensor Replacement - $130-$290 parts and labor.
- EVAP Purge Valve Replacement - $80-$220 parts and labor.
- Fuel Injector Replacement - $260-$520 per injector with labor.
- O2 Sensor Replacement - $160-$320 parts and labor.
Most repairs cost between $100 and $350. The Enclave uses mainstream GM parts, keeping costs reasonable.
Can You DIY This Repair?
MAF cleaning, air filter replacement, and EVAP purge valve replacement are all DIY-friendly. The Enclave has a spacious engine bay that makes access easier than many crossovers. Fuel injector work on the direct injection system is best handled by a professional mechanic.
Prevention Tips
- Replace the air filter every 15,000-20,000 miles
- Use quality fuel from top-tier gas stations
- Add fuel system cleaner every 10,000 miles
- Follow the GM maintenance schedule
- Address check engine lights early to protect the catalytic converters