P0175: System Too Rich Bank 2
What Does P0175 Mean?
P0175 is a diagnostic trouble code indicating: System Too Rich Bank 2. This code relates to the fuel and air metering system. It has been reported in NHTSA complaints across 5 different vehicle models.
Fuel trim is the ECU's real-time adjustment to fuel delivery. Short-term fuel trim (STFT) reacts immediately to O2 sensor feedback, while long-term fuel trim (LTFT) is a learned correction stored in memory. When LTFT exceeds approximately ±25%, the ECU sets a fuel trim code because it's run out of adjustment range. Positive fuel trim means the ECU is adding fuel (lean condition), negative means it's subtracting fuel (rich condition). Understanding fuel trims is key to diagnosing these codes — they tell you the direction and magnitude of the problem.
Fuel trim is the ECU's real-time adjustment to fuel delivery. Short-term fuel trim (STFT) reacts immediately to O2 sensor feedback and fluctuates constantly. Long-term fuel trim (LTFT) is a learned correction stored in memory that compensates for gradual changes like wear and altitude. When LTFT exceeds approximately ±25%, the ECU has run out of adjustment range and sets a fuel trim code. Understanding the difference between STFT and LTFT is key: STFT shows what's happening NOW, LTFT shows the average correction over many drive cycles. At idle, high positive fuel trims suggest vacuum leaks. At cruise, high positive trims suggest fuel delivery issues (pump, filter, pressure). Common affected vehicles: Any vehicle — fuel trim codes are universal and affect all makes equally.
**Real-World Diagnostic Walkthrough:** P0175 (Bank 2 too rich) combined with P0172 (Bank 1 too rich) indicates a system-wide rich condition. Check for: a dirty MAF sensor reading low (causing the ECU to deliver too little air relative to fuel), a leaking fuel pressure regulator (dumping extra fuel into the intake or rail), stuck-open purge valve flooding the engine with fuel vapors, or a faulty coolant temperature sensor telling the ECU the engine is colder than it actually is (causing excess cold-start enrichment). If only P0175 appears without P0172, check for a leaking injector on Bank 2, a Bank 2 O2 sensor stuck reading lean (causing the ECU to over-fuel that bank), or a Bank 2 exhaust leak before the O2 sensor.
Symptoms of P0175
- ⚠️ check engine light
- ⚠️ black exhaust smoke
- ⚠️ fuel smell
- ⚠️ poor fuel economy
- ⚠️ rough idle
- ⚠️ fouled spark plugs
Common Causes
- 🔍 Leaking fuel injectors
- 🔍 Faulty MAF sensor
- 🔍 Stuck-open fuel pressure regulator
- 🔍 Faulty O2 sensor Bank 2
P0175 Reports by Year
Real Owner Reports
From NHTSA complaint database — actual owner descriptions.
"Excessive oil consumption which led to engine misfire while driving and trying to merge onto the freeway. This cause a significant loss of power and poor performance by the vehicle. Fortunately the roadway was not busy, but this issue could have caused an accident. Took the vehicle to local mecha"
— Honda Pilot owner, 05/19/2021
"Honda Technician upon inspection found code p0175 fuel system too rich, preformed af test found bank 2 failed on all injectors, injectors need to be replaced. But the honda dealer is NOT willing to replace the fuel injector based on "SERVICE BULLETIN 20-100, & 20-11 Warranty Extension". The service "
— Honda Pilot owner, 06/02/2025
"2011 NISSAN ALTIMA SR SEDAN 3.5 CVT. WHEN DRIVING, CVT GOES INTO SAFE MODE WITH REDUCED ACCELERATION, INDICATING A TRANSMISSION ISSUE AND WOULD ALSO TRIGGER VEHICLE DYNAMIC CONTROL SYSTEM FAULT.. ORIGINAL ENGINE CODE WAS P0175. HAD MECHANIC REPLACE 31935-1XF00 SPEED SENSOR ASSY. PROBLEM WAS NOT "
— Nissan Altima owner, 12/15/2016
Source: NHTSA Complaints Database
Most Reported Vehicles for P0175
Based on NHTSA owner complaint data.
| # | Vehicle | Reports |
|---|---|---|
| 1 | HONDA PILOT | |
| 2 | NISSAN ALTIMA | |
| 3 | KIA STINGER | |
| 4 | JEEP CHEROKEE | |
| 5 | GMC TERRAIN |
P0175 Reports by Vehicle
Detailed NHTSA complaint analysis for each vehicle model.
Diagnostic Tips
- Read STFT and LTFT at idle AND at 2500 RPM. If both are high at idle but normal at higher RPM, suspect a vacuum leak. If both are high everywhere, suspect fuel delivery (pump, filter, pressure).
- Smoke test the intake system — this is the fastest way to find vacuum leaks that cause lean fuel trims.
- Check fuel pressure with a gauge. Low pressure causes lean codes; high pressure causes rich codes.
- If only one bank shows abnormal fuel trims, the cause is likely isolated to that bank (O2 sensor, exhaust leak, injector on that bank).
Common Mistakes to Avoid
- ❌ Replacing O2 sensors based on fuel trim codes — the sensors are correctly reporting the problem, not causing it.
- ❌ Not checking fuel trims before starting repairs — fuel trim data tells you exactly which direction to investigate.
- ❌ Clearing codes without fixing the root cause — LTFT relearns within a few drive cycles and the code returns.
Frequently Asked Questions
What's the difference between P0172 and P0175?
Can a clogged air filter cause P0175?
What are normal fuel trim values?
How do I read fuel trim data?
What To Do Next
Possible Fixes
- 🔧 Clean or replace MAF sensor
- 🔧 Replace fuel injectors
- 🔧 Replace O2 sensor Bank 2
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1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
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Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
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Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.