What Does P0172 Mean on Your 2020 Chevrolet Traverse?
A P0172 code on the 2020 Chevrolet Traverse means the engine control module has detected that Bank 1 is running too rich. The 2020 Traverse is powered by a 3.6L V6 engine producing 310 horsepower and 266 lb-ft of torque. This naturally aspirated V6 uses direct injection. Bank 1 is the rear bank of the engine, closest to the firewall.
Running rich means the engine is getting more fuel than the optimal 14.7:1 air-to-fuel ratio. This decreases fuel economy, can foul spark plugs, and puts stress on the catalytic converter on Bank 1.
Common Symptoms You May Notice
- Check engine light on
- Reduced fuel economy
- Rough or uneven idle
- Black exhaust smoke
- Fuel smell at the tailpipe
- Possible hesitation during acceleration
Top Causes of P0172 on the 2020 Traverse
- Dirty MAF sensor - The mass airflow sensor accumulates contamination over time, causing inaccurate airflow readings and excess fuel injection.
- Faulty upstream O2 sensor - The Bank 1 upstream oxygen sensor may become sluggish or biased, causing incorrect fuel trim corrections.
- Leaking fuel injector - A direct injection injector on the rear bank that does not seal properly delivers excess fuel.
- EVAP purge valve stuck open - A malfunctioning purge valve sends continuous fuel vapors into the intake manifold.
How to Diagnose the Problem
Scan for codes and review freeze frame data. Check Bank 1 STFT and LTFT. Negative LTFT beyond -10% confirms the rich condition.
Replace the air filter if needed and clean the MAF sensor with dedicated MAF cleaner spray. This is the most effective first step for P0172.
Monitor the Bank 1 upstream O2 sensor with live data. It should oscillate between 0.1V and 0.9V. A sensor that stays above 0.5V consistently indicates a rich condition. Test fuel pressure if other checks are normal.
Repair Options and Cost Estimates
- MAF sensor cleaning or replacement: Cleaning under $10. New sensor $50-$165 plus $45-$95 labor.
- O2 sensor replacement: Parts $50-$150. Labor $80-$155.
- Fuel injector replacement: Parts $40-$110 per injector. Labor $200-$420.
- EVAP purge valve: Parts $25-$55. Labor $50-$100.
Can You Fix This Yourself?
MAF cleaning is easy. O2 sensor replacement requires getting under the vehicle and may be tight near the rear bank. Fuel injector replacement on the direct injection system is best left to a professional.
Prevention Tips
- Replace the air filter every 15,000-20,000 miles
- Use Top Tier fuel to keep direct injectors clean
- Run fuel system cleaner every 5,000 miles
- Address check engine lights promptly