P0174 on the 2022 Lincoln Nautilus: What It Means
The 2022 Lincoln Nautilus offers two turbocharged engines: a 2.0L turbo four-cylinder EcoBoost (250 hp) and a 2.7L twin-turbo V6 EcoBoost (335 hp). P0174 indicates a lean condition on Bank 2 — the PCM has detected excess air or insufficient fuel. On the four-cylinder, this is a generalized lean state. On the 2.7L V6, Bank 2 is a specific cylinder bank running lean.
Symptoms
- Check engine light illuminated
- Rough or unstable idle
- Hesitation during acceleration
- Reduced turbo boost response
- Decreased fuel economy
Common Causes on the Nautilus
1. Boost Leaks
Both Nautilus engines are turbocharged with charge piping, intercoolers, and multiple coupler connections. On the 2.0T, check the charge pipe to throttle body connection, intercooler hoses, and diverter valve. On the 2.7L twin-turbo, the dual charge pipe arrangement means Bank 2-specific leaks are possible. A boost leak test at 15-20 psi is the most effective diagnostic tool.
2. MAF Sensor Contamination
The hot-wire MAF sensor sits in the intake duct upstream of the turbocharger. PCV oil vapor and environmental contaminants can coat the sensing element. On the 2.7L twin-turbo, high airflow volume makes MAF accuracy critical. Clean with MAF-specific spray before considering replacement.
3. Fuel System Issues
The 2.0T uses direct injection, while the 2.7T uses port and direct injection (PFDI). A weak high-pressure fuel pump, restricted injector, or failing port injector can cause lean conditions. The 2.7T's dual fuel system adds complexity but also more potential failure points.
4. PCV System Malfunction
Turbo engines generate crankcase pressure that the PCV system must manage. A stuck PCV valve or torn hose introduces unmetered air into the intake. Inspect the PCV valve and all connecting hoses for damage.
Diagnostic Steps
- Scan with FORScan for all DTCs and freeze frame data
- Identify engine variant (2.0T or 2.7T)
- Check long-term fuel trim values for both banks
- Boost leak test the charge air system
- Clean and test MAF sensor
- Monitor fuel pressure under various conditions
Repair Costs for the 2022 Nautilus
- Boost leak repair: $200–$500
- MAF sensor cleaning: $25–$45 (DIY)
- MAF sensor replacement: $180–$380
- High-pressure fuel pump: $600–$1,000
- PCV valve or hose repair: $80–$250
Can You Drive With P0174?
Both Nautilus engines are turbocharged, making lean conditions concerning under boost. Avoid hard acceleration and spirited driving. The 2.7L twin-turbo is particularly sensitive to lean conditions due to its higher boost pressures. Have it diagnosed within a week. The 2022 model may still be within Lincoln's 4-year/50,000-mile warranty.
DIY Feasibility
The Nautilus engine bay is moderately accessible. MAF sensor cleaning takes 10 minutes. Boost pipe inspection is manageable though some connections are harder to reach. FORScan provides excellent diagnostic access for Ford/Lincoln vehicles. Under warranty, dealer service is the best option.