P0175: How to Diagnose & Fix — System Too Rich (Bank 2)
4 vehicles · 4 makes · $50-$500 repair
How to diagnose and fix P0175: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Volvo 850 · 1993–1997
The fuel pressure regulator (FPR) on the 850 is mounted on the fuel rail and uses a rubber diaphragm to regulate fuel pressure. The diaphragm deteriorates with age and heat exposure, allowing raw fuel to leak into the vacuum line connected to the intake manifold. This causes rich running, hard starting (especially hot), poor fuel economy, and a strong fuel smell. It can also foul spark plugs.
Common Symptoms
- Strong fuel smell from engine bay
- Hard hot starting
- Rich running and black exhaust smoke
- Poor fuel economy
- Fouled spark plugs
How to Fix
Replace the fuel pressure regulator. Check the vacuum line for fuel contamination and replace if saturated. Inspect and replace fouled spark plugs. The FPR is inexpensive ($30-$60) and accessible on top of the fuel rail, making this a straightforward DIY repair. Clear any stored fault codes after replacement.
Kia Telluride · 2020–2025
The 3.8L Lambda II V6 in the Telluride experiences fuel dilution of the engine oil when driven primarily on short trips (under 10 miles). Fuel washes past the piston rings during cold starts and does not fully evaporate because the oil never reaches full operating temperature. The diluted oil has reduced viscosity and lubrication properties, accelerating engine wear. The issue is more pronounced in cold climates. Oil analysis shows fuel contamination levels of 3-5% in severe cases.
Common Symptoms
- Oil level rising above the full mark on dipstick
- Gasoline smell from engine oil on dipstick
- Oil appearing thinner than normal
- Oil change interval warning appearing early
- Increased engine noise from reduced oil film strength
How to Fix
Change oil more frequently if driving primarily short trips — every 3,000-4,000 miles instead of the 7,500-mile factory interval. Take the vehicle on a 20+ minute highway drive weekly to bring the oil to full operating temperature and boil off fuel contamination. Use a quality full-synthetic 5W-30 oil that resists fuel dilution better than conventional oil. Consider oil analysis testing (Blackstone Labs, $30) to monitor fuel dilution levels. If fuel dilution exceeds 5%, investigate injector spray patterns.
Sources for this issue (1)
Audi S8 · 2013–2018
Audi TSB 2046724/5 covers sporadic warm-engine no-start or long cranking after the vehicle sits without fully cooling. A rich-mixture DTC may occur, but often there is no DTC. Audi’s procedure distinguishes fuel in the oil from a short-trip profile, ECM software, high-pressure injector leakage and high-pressure fuel-pump leakage rather than assuming one failed component.
Common Symptoms
- Warm-soak no-start with normal starter operation
- Long cranking followed by rough running for a few seconds
How to Fix
Have the dealer read DTCs and ODIS fuel-in-oil value, verify ECM software and perform Audi’s high- and low-pressure holding tests. If high-pressure behavior is abnormal, borescope the combustion chamber to identify a leaking injector. If low-side pressure builds correctly but drops more than 1.5 bar in the first 15 minutes, Audi says at least one HPFP may be leaking and directs replacement of both pumps plus an oil change. Select no pump or injector until the test identifies the path.
Owner tips & cautions
- TipRecord engine temperature and how long the car sat before the hard start; do not approve pumps or injectors without the pressure-hold results.
Sources for this issue (1)
GMC Jimmy · 1996–2001
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P0175 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0175 mean?
P0175 stands for "System Too Rich (Bank 2)." P0175 is a generic OBD-II code meaning the engine computer detected that the air-fuel mixture on bank 2 is too rich, with too much fuel relative to air. The computer has had to remove fuel (negative fuel trim) to try to correct it but has reached its adjustment limit. Bank 2 is the cylinder bank that does not contain cylinder #1. A persistently rich mixture wastes fuel, causes rough running, and can overheat and damage the catalytic converter over time.
What are the most common causes of P0175?
The most common causes of P0175 are: Dirty or faulty mass air flow (MAF) sensor, Leaking or stuck-open fuel injector, Excessive fuel pressure / faulty fuel pressure regulator, Faulty or contaminated oxygen sensor, Engine vacuum leak or false air reading, Dirty/clogged air filter or restricted intake, Leaking fuel injector O-rings or fuel saturation, Faulty coolant temperature sensor skewing fuel trims. The specific cause varies by vehicle.
How much does it cost to fix P0175?
Repair costs for P0175 range from $50 to $500, depending on the vehicle and root cause.
Which vehicles are affected by P0175?
Au7o has documented P0175 across 4 vehicle models from 4 manufacturers: Audi, GMC, Kia, Volvo.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.