What Does P0172 Mean on Your 2024 Lincoln Navigator?
A P0172 code on your 2024 Lincoln Navigator indicates the PCM has detected that Bank 1 is running richer than the target air-fuel ratio. The 2024 Navigator uses Ford's 3.5-liter twin-turbocharged EcoBoost V6 producing 440 hp, paired with a 10-speed automatic. Bank 1 is the passenger-side cylinder bank.
Running rich means excess fuel relative to air in the combustion mixture. The twin-turbo direct injection system is complex, with multiple potential failure points that can cause a rich condition.
Symptoms You May Notice
- Check engine light on
- Fuel economy below the rated 16/22 mpg
- Rough idle
- Black exhaust smoke
- Fuel smell from exhaust
- Turbo lag or reduced power
- Bank 1 misfires
Common Causes of P0172 on the 2024 Lincoln Navigator
- Dirty MAF Sensor - Oil vapor contamination from the turbo inlet is the top cause. The MAF underreads airflow when dirty.
- Boost System Leak - Twin-turbo charge piping has many connections. Any leak reduces actual airflow to the engine.
- Leaking Fuel Injector - High-pressure direct injectors on Bank 1 can develop leaks.
- Failing O2 Sensor (Bank 1) - A sluggish upstream O2 sensor provides inaccurate feedback.
How to Diagnose P0172
- Scan all codes - Check for P0175, boost, MAF, and O2 companion codes.
- Review fuel trims - Compare Bank 1 and Bank 2 LTFT values.
- Clean the MAF - Best first step.
- Boost leak test - Check all charge pipe connections.
- Monitor O2 sensors - Check Bank 1 Sensor 1 response.
- Test injectors - Check Bank 1 for leaks and balance.
Repair Options and Cost Breakdown
- MAF Cleaning - $15-$30 DIY.
- MAF Replacement - $190-$420 parts and labor.
- Boost Pipe Repair - $130-$520 depending on the component.
- Fuel Injector Replacement - $380-$780 per injector.
- O2 Sensor Replacement - $230-$440 parts and labor.
Most repairs cost $200 to $560. Warranty coverage may apply for the 2024 model year.
Can You DIY This Repair?
MAF cleaning is straightforward. The Navigator's large engine bay provides good access. Boost hose inspection is feasible. Injector and turbo system work requires professional equipment. Ford/Lincoln specialists offer competitive pricing versus the dealer.
Prevention Tips
- Replace the air filter every 15,000-20,000 miles
- Use quality fuel from top-tier stations
- Add fuel system cleaner every 10,000 miles
- Have turbo system inspected during scheduled service
- Address check engine lights promptly