P0171 on Your 2023 GMC Yukon: What It Means
When your 2023 GMC Yukon shows a P0171 code, the engine control module is telling you that Bank 1 is running lean. The 2023 Yukon is available with the 5.3L V8 (L84), 6.2L V8 (L87), or 3.0L Duramax diesel. This code only applies to the gasoline engines. Running lean means there is more air than fuel in the combustion mixture on Bank 1, which is the passenger side of the engine.
Even on a relatively new full-size SUV, P0171 can occur. Let us explore the most likely causes and how to get it fixed.
Symptoms
- Check engine light on
- Rough or slightly unstable idle
- Reduced acceleration response
- Fuel economy dropping below normal
- Occasional stumble or hesitation
- Engine may run hotter than typical
Top Causes on the 2023 Yukon
- EVAP Purge Valve Stuck Open (30% likelihood) - A persistent GM issue across their V8 truck and SUV lineup. The purge solenoid can fail open, introducing unmetered air through the evaporative emission system.
- Vacuum Leak (25% likelihood) - Even on newer vehicles, a loose hose clamp, improperly seated gasket, or cracked vacuum line can allow unmetered air into the intake.
- MAF Sensor Issue (25% likelihood) - Contamination from aftermarket air filters or a factory-defective sensor can cause inaccurate airflow readings.
- Fuel Delivery Problem (20% likelihood) - A defective fuel injector or fuel pressure regulator issue can cause lean conditions on one bank.
How to Diagnose
- Check for TSBs. GM may have a service bulletin for P0171 on the 2023 Yukon. The dealer should check this during diagnosis.
- Test the EVAP purge valve. Command it closed via scan tool and monitor fuel trims. Improvement indicates a stuck valve.
- Monitor fuel trims. LTFT above +10% on Bank 1 confirms the lean reading.
- Inspect vacuum connections. Look for loose clamps, cracked hoses, or improperly seated gaskets.
- Evaluate MAF sensor. Compare readings to factory specs. Clean with dedicated MAF cleaner if contaminated.
Repair Costs
- Under warranty: $0. The 2023 Yukon is covered under GM's factory warranty.
- EVAP purge valve (out of warranty): $50 - $200.
- Vacuum leak repair (out of warranty): $75 - $400.
- MAF sensor replacement (out of warranty): $200 - $320.
- Fuel injector replacement (out of warranty): $300 - $800.
Warranty Information
Your 2023 GMC Yukon is covered by a 3-year/36,000-mile bumper-to-bumper warranty and a 5-year/60,000-mile powertrain warranty. P0171 is a powertrain code, so the repair should be fully covered. Visit your authorized GMC dealer and let them handle the diagnosis and repair.
Prevention Tips
- Use OEM dry air filters to keep the MAF sensor clean
- Fill up with Top Tier gasoline
- Do not delay dealer visits when the check engine light comes on
- Keep all service records for warranty documentation
- Follow the factory maintenance schedule