What Does P0172 Mean on Your 2023 Ford Bronco Sport?
A P0172 code on the 2023 Ford Bronco Sport means the powertrain control module has detected that Bank 1 is running too rich. The 2023 Bronco Sport offers the 1.5L EcoBoost turbocharged three-cylinder (181 hp) as the base engine and the 2.0L EcoBoost turbocharged four-cylinder (250 hp) on the Badlands trim. Both are inline engines with a single bank, and both use turbocharging with direct fuel injection.
Running rich means the engine is getting more fuel than the ideal 14.7:1 air-to-fuel ratio calls for. This leads to wasted fuel, carbon buildup on spark plugs, and potential catalytic converter damage over time.
Common Symptoms You May Notice
- Check engine light on the dash
- Decreased miles per gallon
- Rough or surging idle
- Black smoke from the exhaust
- Fuel odor near the tailpipe
- Sluggish throttle response
Top Causes of P0172 on the 2023 Bronco Sport
- Contaminated mass airflow sensor - Dust and debris from everyday driving or light trail use contaminates the MAF element, causing it to underreport airflow and trigger over-fueling.
- Turbo boost leak - The charge pipes, intercooler hoses, and associated clamps can develop leaks that allow air to escape after the MAF has measured it.
- Degraded upstream O2 sensor - A sluggish oxygen sensor on the exhaust gives the PCM inaccurate feedback for fuel trim calculations.
- Leaking fuel injector - A direct injection injector that does not close completely delivers excess fuel to the cylinder.
How to Diagnose the Problem
Pull codes with an OBD-II scanner and check freeze frame data. Examine Bank 1 fuel trims. LTFT more negative than -10% confirms the rich condition.
Replace the air filter if it is dirty and clean the MAF sensor with MAF-specific cleaner spray. This is the most common and effective first step for P0172 on EcoBoost engines.
Check all turbo boost connections for tightness and integrity. Pay attention to the intercooler hose clamps. A smoke test is the best method for finding small leaks.
Use live scan data to watch the upstream O2 sensor. It should oscillate quickly between 0.1V and 0.9V. If it stays above 0.5V consistently, the engine is confirmed rich.
Repair Options and Cost Estimates
- MAF sensor cleaning or replacement: Cleaning is under $10. New sensor is $50-$165 plus $45-$100 labor.
- Boost leak repair: Hoses and clamps cost $20-$75. Labor is $70-$175.
- O2 sensor replacement: Parts are $50-$150. Labor runs $70-$140.
- Fuel injector replacement: Parts cost $40-$115 each. Labor is $170-$360.
Can You Fix This Yourself?
MAF cleaning is the easiest starting point. Checking boost hoses takes minimal tools. O2 sensor replacement is moderate difficulty. Fuel injector work on the direct injection system is advanced and better suited for a shop.
Prevention Tips
- Change the air filter regularly, especially after driving on dusty roads
- Inspect turbo hose clamps during oil changes
- Use Top Tier fuel to keep the fuel system clean
- Run a fuel system cleaner every 5,000 miles