System Too Rich (Bank 2)
The P0175 code means the vehicle's onboard diagnostic system has detected: System Too Rich (Bank 2). This is a serious severity code.
- Keep driving?
- Yes, but fix soon
- DIY difficulty
- medium
- Estimated cost
- $0-$400
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Common Symptoms
- Check Engine Light on
- Rich smell from exhaust
- Poor fuel economy
- Black smoke
- Rough idle on Bank 2
Probable Causes (Ranked by Likelihood)
- Leaking injectors on Bank 2 Very High
- High fuel pressure affecting all injectors High
- MAF sensor over-reading (affects both banks) High
- Faulty Bank 2 O2 sensor causing rich correction Moderate
- Stuck purge valve flooding intake Moderate
Step-by-Step Diagnostic Procedure
-
Check LTFT on both banks. If both are negative, suspect shared components (MAF, fuel pressure).
-
If only Bank 2 LTFT is negative, focus on Bank 2 specific injectors or the Bank 2 upstream O2 sensor.
-
Follow the same diagnostic approach as P0172 but targeted at Bank 2.
Common Fixes by Vehicle
What techs usually find when diagnosing P0175 on specific vehicles — tap your vehicle for the fix and the exact part:
2009-2020 Ford F-150/Expedition 3.5L EcoBoost Moderate DIY
Bank 2 (passenger side) running rich. On EcoBoost engines, check for leaking fuel injectors on Bank 2 using a fuel injector balance test. Also check the MAF sensor for contamination from oiled air filters. A cracked intercooler or leaking charge pipe causes incorrect boost readings that make the ECU add too much fuel. Clean the MAF with CRC MAF cleaner.
Labor: 1-2 hours2005-2014 Ford F-150/Expedition 5.4L 3V Moderate DIY
Bank 2 rich on the 5.4L V8. Check for a leaking fuel pressure regulator -- sniff or look for fuel in the vacuum line connected to the regulator. Also check the Bank 2 upstream O2 sensor for contamination from coolant (cracked intake manifold). A stuck-open EVAP purge valve can also cause rich on both banks. Clean the MAF sensor first.
Labor: 30 min2010-2020 Chevrolet Silverado/Tahoe 5.3L Easy DIY
Bank 2 system too rich. Check the EVAP purge solenoid (ACDelco 214-2149) for sticking open -- this dumps fuel vapor into the intake causing a rich condition. Command the purge valve closed with a scan tool and monitor fuel trims. Also check for a leaking Bank 2 fuel injector. On AFM-equipped engines, excessive oil consumption can foul the Bank 2 O2 sensor.
Labor: 20-30 min2009-2019 Dodge Ram 5.7L Hemi Easy (MAF), Advanced (manifold) DIY
Bank 2 running rich on the Hemi. Check for a cracked passenger side exhaust manifold first -- exhaust leaks cause the O2 sensor to read incorrectly, and the ECU compensates by adding fuel. If no exhaust leak, check fuel injector spray pattern and MAF sensor accuracy. Clean the MAF sensor with CRC MAF cleaner as a first step.
Labor: 10 min (MAF), 3-4 hours (manifold)Frequently Asked Questions
If P0172 and P0175 appear together, does that mean both banks are rich?
Yes. When both banks run rich simultaneously, the cause is almost always a shared component: MAF sensor over-reading, high fuel pressure, or a purge valve stuck open dumping fuel vapor into the intake.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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