OBD-II trouble code
P0175: System Too Rich (Bank 2)
The engine computer detected that Bank 2 is running with too much fuel or too little air. Same condition as P0172, but on the opposite side of a V-configured engine. Only applies to V engines.
Quick facts
- System
- Powertrain
- Category
- Fuel and Air Metering
- Severity
- Medium severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $50 – $1,000
- DIY difficulty
- Intermediate DIY
What does P0175 mean?
P0175 is the Bank 2 equivalent of P0172. The engine control module (ECM) monitors the air-fuel mixture using oxygen sensors and adjusts fuel injection to keep combustion ideal. "Rich" means there is too much fuel relative to air. When long-term fuel trim on Bank 2 drops below roughly -10% to -25% for an extended period (the exact threshold varies by manufacturer), the ECM sets P0175.
Bank 2 refers to the side of the engine that does not contain cylinder 1. P0175 only applies to V-configuration engines (V6, V8, etc.) and a small number of horizontally-opposed and inline configurations with dual oxygen sensor banks. Inline engines with a single bank cannot set P0175.
It's not unusual to see P0172 and P0175 together on aging V engines when the cause is a shared component — a failing MAF sensor reading low, a stuck-closed fuel pressure regulator, or faulty temperature sensors. When only P0175 is set, focus on Bank 2 components: a leaking Bank 2 fuel injector or a Bank 2 oxygen sensor reading inaccurately lean.
Common causes
- Leaking Bank 2 fuel injector (stuck partially open)
- Dirty or failing mass airflow (MAF) sensor reading low — if both banks affected
- Faulty Bank 2 upstream oxygen sensor reading lean (commands extra fuel)
- High fuel pressure from a failed pressure regulator (affects both banks)
- Faulty engine coolant temperature sensor reading cold
- Faulty intake air temperature sensor reading cold
- Restricted air intake limiting air to Bank 2
- Saturated charcoal canister dumping fuel vapor disproportionately to Bank 2 intake
Symptoms
- Check engine light is on
- Black smoke from the exhaust on acceleration
- Strong fuel smell
- Reduced fuel economy
- Rough idle
- Hard starting (flooded condition)
- Fouled spark plugs, especially on the Bank 2 side
- Failed emissions test
Diagnostic steps
- 1.Check whether P0172 is also set. Both rich codes together point to a shared cause — start with MAF, fuel pressure regulator, and shared sensors.
- 2.If only P0175 is set, focus on Bank 2 components: Bank 2 injectors, Bank 2 oxygen sensor, and Bank 2 intake.
- 3.Scan fuel trims for both banks. If Bank 2 LTFT is significantly more negative than Bank 1, the problem is isolated.
- 4.Inspect Bank 2 spark plugs for fouling — black sooty plugs confirm the rich condition.
- 5.Test fuel pressure against manufacturer specification.
- 6.Test Bank 2 upstream oxygen sensor signal — slow switching or stuck-lean readings cause the ECM to over-fuel that bank.
- 7.Inspect Bank 2 fuel injectors for leakage.
Repair cost
$50 – $1,000
Air filter or sensor cleaning $20 to $80. Coolant or intake air temperature sensor replacement $100 to $250. MAF sensor replacement $150 to $450. Bank 2 oxygen sensor replacement $150 to $400. Bank 2 fuel injector cleaning or replacement $200 to $1,000 depending on number affected.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with mass airflow sensor replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.