P0175 — System Too Rich — Bank 2
P0175 is the standardized powertrain DTC for “System Too Rich — Bank 2.” The code identifies the monitored condition; it does not by itself prove which part failed.
What P0175 means
P0175 is the standardized powertrain DTC for “System Too Rich — Bank 2.” The code identifies the monitored condition; it does not by itself prove which part failed.
Bank/sensor location note
Bank 2 is the cylinder bank opposite Bank 1. Bank 1 contains cylinder No. 1. Physical left/right location varies by engine and installation, so verify service information before replacing a bank-specific component.
Possible symptoms
- Check Engine Light
- Fuel odor or black exhaust smoke
- Poor fuel economy
- Rough idle or fouled spark plugs
- Negative fuel trims
Causes to test
These are diagnostic possibilities, not a statistical parts-replacement ranking. Vehicle-specific service information takes priority.
- Leaking or over-fueling injector
- Fuel pressure too high
- Biased MAF/MAP or temperature input
- EVAP purge valve stuck open
- Restricted air intake
- O2/A/F sensor or exhaust issue causing incorrect feedback
Step-by-step diagnostic workflow
- Compare STFT/LTFT at idle and higher RPM.
- Check fuel pressure and pressure decay; investigate injector leakage where indicated.
- Verify coolant and intake-air temperature readings are plausible on a cold engine.
- Check MAF/MAP load calculation and inspect for airflow restriction.
- Command or isolate purge flow if service information allows.
- Inspect plugs and upstream sensor response before replacing parts.
Scan data worth checking
- STFT and LTFT
- Fuel pressure
- ECT and IAT from cold start
- MAF/MAP data
- Purge command
- Upstream O2/A/F sensor data
Severity and drivability
Moderate. Excess fuel can foul plugs, dilute engine oil, reduce fuel economy, and overheat the catalyst.
Stop driving and investigate immediately if there is a flashing MIL, oil-pressure warning, overheating, fuel leakage, severe misfire, major loss of power, abnormal mechanical noise, or a transmission that is slipping badly.
Common diagnostic mistakes
- Replacing O2 sensors without verifying fuel pressure or injector leakage
- Ignoring a stuck purge valve
- Assuming a rich code means the fuel pump is bad
Related generic codes
Source and accuracy notes
Generic DTC structure and standardized definitions are governed by SAE J2012/J2012DA. Actual enable criteria, thresholds, circuit pinouts, test values, software conditions, and repair procedures vary by vehicle. Use current OEM service information for the exact year/engine/calibration and check applicable manufacturer technical service bulletins. See the site methodology and primary-reference policy.