What Does P0171 Mean on a 2020 Chevrolet Traverse?
A P0171 code on your 2020 Chevrolet Traverse means the engine control module detected a lean air-fuel mixture on Bank 1. The 2020 Traverse is powered by a 3.6L V6 engine (LFY) producing 310 horsepower. On this transversely-mounted V6, Bank 1 is typically the rear cylinder bank (closest to the firewall). A lean condition indicates too much air or insufficient fuel reaching those cylinders.
The 3.6L V6 is a proven engine that GM uses across many models. While generally reliable, lean conditions can develop from several well-known causes. Let's walk through them.
Symptoms You Might Notice
- Check engine light illuminated
- Rough or uneven idle
- Hesitation when accelerating or merging
- Reduced fuel economy
- Engine may surge at steady speed
- Possible misfires on Bank 1 cylinders
Common Causes of P0171 on the 2020 Chevrolet Traverse
- Intake Manifold Gasket Leak (30% likelihood) - The intake manifold gaskets on the 3.6L V6 can develop leaks that allow unmetered air into specific cylinder banks.
- MAF Sensor Contamination (25% likelihood) - The mass airflow sensor accumulates contaminants over time, causing it to underreport airflow to the PCM.
- Fuel Injector Issue (25% likelihood) - The 3.6L uses direct injection, and carbon buildup on injector tips can restrict fuel delivery. This is a known issue on high-mileage DI engines.
- PCV System Leak (20% likelihood) - Cracked PCV hoses or a failed PCV valve assembly allows unmetered air into the intake system.
How to Diagnose the Problem
- Scan for all codes - Check if P0174 (Bank 2 lean) is present too. Both banks lean suggests MAF or fuel pressure. Only Bank 1 points to a localized issue.
- Monitor fuel trims - Compare Bank 1 and Bank 2 LTFT. Trims above +10% on Bank 1 only suggest an intake leak or injector problem on that bank.
- Smoke test the intake - Inject smoke into the intake to find gasket leaks, cracked hoses, or loose connections. Focus on the rear bank intake runner area.
- Test the MAF sensor - Compare grams-per-second readings to GM specifications for the 3.6L V6.
- Check fuel pressure - Monitor high-pressure fuel rail readings at idle and under load.
Repair Options and Cost Breakdown
- Intake manifold gasket replacement - $300 to $600. Moderate labor on the transverse V6 due to access limitations.
- MAF sensor cleaning/replacement - $50 to $300. Easy to access and clean; replacement sensor runs $100-$200.
- Fuel injector cleaning or replacement - $250 to $650. Professional walnut blasting for carbon removal is common on the 3.6L.
- PCV valve and hose replacement - $80 to $250. Affordable parts with moderate labor.
Can You DIY This Repair?
MAF sensor cleaning is easy on the Traverse. PCV hose inspection and replacement are doable for most DIYers. Intake manifold work on a transverse V6 is more challenging due to tight packaging. Fuel injector work requires specialized equipment.
Prevention Tips
- Change the air filter every 15,000-20,000 miles
- Use Top Tier gasoline to reduce carbon deposits on direct injection components
- Inspect PCV hoses during oil changes for cracking
- Consider a fuel system cleaning every 40,000 miles
- Follow GM's maintenance schedule faithfully