What Does P0172 Mean on Your 2024 Lincoln Nautilus?
A P0172 code on your 2024 Lincoln Nautilus means the PCM has detected a rich air-fuel mixture on Bank 1. The 2024 Nautilus features a 2.0-liter turbocharged 4-cylinder engine producing 250 hp with an 8-speed automatic transmission. As an inline-4, there is only one bank, so P0172 affects the entire engine.
Running rich means the engine is receiving more fuel than the ideal 14.7:1 stoichiometric ratio. The PCM monitors this through oxygen sensors and sets the code when normal fuel trim corrections are insufficient.
Symptoms You May Notice
- Check engine light on
- Reduced fuel economy below the rated 22/29 mpg
- Rough idle
- Dark exhaust smoke
- Fuel smell from exhaust
- Hesitation or reduced power
- Possible misfires
Common Causes of P0172 on the 2024 Lincoln Nautilus
- Dirty MAF Sensor - Oil vapor contamination from the turbo intake system causes inaccurate airflow readings. The most common and cheapest fix.
- Boost System Leak - Charge pipe or intercooler connection leaks reduce actual boost pressure reaching the engine.
- Leaking Fuel Injector - Direct injection injectors operating at high pressures can develop leaks.
- Failing Upstream O2 Sensor - A slow-responding sensor provides incorrect data to the PCM.
How to Diagnose P0172
- Scan all codes - Look for boost, MAF, and O2 companion codes.
- Review fuel trims - Negative LTFT beyond -10% confirms the rich condition.
- Clean the MAF - Best first step.
- Check boost system - Test for leaks in all charge pipe connections.
- Monitor O2 sensor - Check upstream sensor response time.
- Test injectors - Check for leaks and proper fuel delivery.
Repair Options and Cost Breakdown
- MAF Cleaning - $15-$30 DIY.
- MAF Replacement - $180-$400 parts and labor.
- Boost Pipe Repair - $100-$400 depending on component.
- Fuel Injector Replacement - $330-$720 per injector.
- O2 Sensor Replacement - $210-$410 parts and labor.
Most repairs cost $180 to $500. Warranty coverage may apply for the 2024 model year.
Can You DIY This Repair?
MAF cleaning and air filter replacement are easy DIY tasks. Boost hose inspection is feasible. The 2024 Nautilus engine bay is reasonably accessible for basic maintenance. Fuel injector work should be handled by a professional.
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 service
- Address check engine lights early