What Does P0172 Mean on Your 2023 GMC Yukon?
If your 2023 GMC Yukon has triggered a P0172 code, the engine control module has detected that Bank 1 is running richer than it should. The 2023 Yukon uses either the 5.3L L84 V8 (355 hp) or the 6.2L L87 V8 (420 hp), both with direct injection and Dynamic Fuel Management. Bank 1 is the driver's side cylinder bank on these V8s.
A rich condition on the Yukon's V8 means extra fuel is being burned, costing you at the pump and potentially harming emissions components. Since this is a newer vehicle, warranty coverage may still apply.
Symptoms You Might Notice
- Check engine light on
- Lower fuel economy
- Rough idle or slight vibration
- Black smoke from the exhaust
- Fuel smell at the exhaust
- Reduced DFM efficiency
Common Causes of P0172 on the 2023 GMC Yukon
- Dirty MAF Sensor — Contamination from an aftermarket oiled air filter or road debris. The MAF underestimates airflow, causing the ECM to overfuel.
- EVAP Purge Valve Stuck Open — A well-known GM issue where the purge solenoid fails and allows constant fuel vapor entry into the intake.
- Faulty Upstream O2 Sensor — An early failure or defect in the Bank 1 Sensor 1 oxygen sensor.
- Leaking Fuel Injector — A direct fuel injector that doesn't seal properly, allowing fuel seepage.
How to Diagnose the Problem
- Retrieve all DTCs — Check for companion codes like P0175 or EVAP-related codes.
- Analyze fuel trim data — Compare Bank 1 and Bank 2 LTFT values.
- Test MAF sensor accuracy — Compare readings to GM specs for your engine variant.
- Test the purge valve — Command it open/closed and verify it seals properly.
- Monitor O2 sensor live data — Check voltage switching speed and range.
- Perform injector diagnostics — Cylinder balance and flow tests.
Repair Options and Cost Estimates
Your 2023 Yukon may still be under GM's 3-year/36,000-mile warranty or 5-year/60,000-mile powertrain warranty. Check with your dealer.
- MAF Sensor Cleaning — DIY: $10-$15. Shop: $65-$130.
- MAF Sensor Replacement — Parts: $85-$200, labor: $65-$130. Total: $150-$330.
- Purge Valve Replacement — Parts: $25-$65, labor: $65-$130. Total: $90-$195.
- O2 Sensor Replacement — Parts: $85-$210, labor: $100-$190. Total: $185-$400.
- Fuel Injector Replacement — Parts: $65-$180, labor: $260-$475. Total: $325-$655.
Can You Fix This Yourself?
If under warranty, let the dealer handle it. Otherwise, MAF sensor cleaning is a great DIY starting point. Purge valve replacement is also straightforward on the Yukon. Leave injector work to the professionals.
Prevention Tips
- Stick with OEM or quality dry air filters
- Use Top Tier gasoline
- Follow GM's recommended maintenance schedule
- Address check engine lights promptly to prevent secondary damage