P0175 on the 2019 Ford Explorer
The 2019 Ford Explorer is the final year of the fifth generation, using the front-wheel-drive-based D4 platform. It was available with the 3.5L Ti-VCT V6 (290 hp), the 2.3L EcoBoost four-cylinder (280 hp), or the 3.5L EcoBoost V6 in the Sport and Platinum trims (365 hp). A P0175 code means the PCM has detected that Bank 2 is running too rich. On the V6 engines, Bank 2 is the cylinder bank opposite from cylinder one. With most 2019 models at 50,000-100,000 miles, age-related wear is a factor in diagnosis.
Transverse Engine Layout
Unlike the newer rear-drive-based Explorer, the 2019 model has a transverse-mounted engine. This means the exhaust manifolds and O2 sensors are closer to the firewall and more difficult to access. The transverse layout also results in tighter underhood packaging, where heat soak can accelerate component wear on the rear-facing Bank 2 side.
Symptoms to Watch For
- Check engine light illuminated
- Fuel economy below the 16 city / 22 highway MPG baseline
- Black exhaust smoke or sooty residue
- Rough or uneven idle
- Hesitation during acceleration, especially from a cold start
- Exhaust has a gasoline odor
- May fail state emissions testing
Likely Causes at This Mileage
1. Aging O2 Sensor on Bank 2
At 50,000-100,000 miles, the upstream O2 sensor on Bank 2 is the most likely cause. On the 2019 Explorer, the Bank 2 sensor faces the firewall where airflow is restricted and heat buildup is greater. This environment accelerates sensor aging. A worn sensor provides sluggish or inaccurate feedback, causing the PCM to continuously add fuel beyond what is needed.
2. Contaminated MAF Sensor
Years of operation have allowed dust, PCV vapors, and environmental contaminants to accumulate on the MAF sensor. On the 3.5L naturally aspirated V6, the MAF is in the intake tube after the air filter box. On the EcoBoost models, it is before the turbo inlet. Cleaning takes minutes and costs almost nothing. This should always be your first diagnostic step.
3. Leaking Fuel Injector
The 3.5L Ti-VCT uses port injection, while the EcoBoost engines use direct injection. On the port-injected 3.5L, injectors can develop worn pintle seats or deteriorated O-rings at this mileage, allowing fuel to drip into the intake port. On the direct-injection EcoBoost, carbon deposits on injector tips can alter spray patterns and flow rates.
4. Fuel Pressure Regulator Failure
On the naturally aspirated 3.5L V6, the fuel pressure regulator maintains consistent rail pressure. A failing regulator with a ruptured diaphragm allows fuel to be drawn into the intake through the vacuum line. You can diagnose this by disconnecting the vacuum line from the regulator and checking for liquid fuel, which should not be present.
How to Diagnose
- Identify your engine type and scan for all stored codes
- Check freeze frame data for operating conditions at code set
- Monitor Bank 1 and Bank 2 fuel trims at idle and 2,500 RPM
- Clean the MAF sensor with dedicated spray
- Test Bank 2 upstream O2 sensor with live data for switching speed
- On the NA 3.5L, check the fuel pressure regulator vacuum line for fuel
- Perform injector balance test or leak-down test
- Check for vacuum leaks with a smoke test
Expected Repair Costs
O2 sensor replacement on the 2019 Explorer costs $120-$300. MAF sensor cleaning is under $15. Fuel injector replacement runs $180-$500 per injector on the NA V6, or $250-$650 per injector on EcoBoost models. Fuel pressure regulator replacement costs $150-$350. These are reasonable maintenance costs for a vehicle at this mileage.
Is It Worth Fixing?
Absolutely. The repair cost for P0175 is typically $120-$350 for the most common causes. Ignoring it risks catalytic converter failure, which costs $1,000-$2,500 on the Explorer. The 2019 Explorer is a capable family SUV worth maintaining, and this is a straightforward repair at any independent shop or Ford dealer.