P0175
System Too Rich (Bank 2)
- Severity
- Medium
- Driving
- Drivable — book it in
The engine is running rich on bank 2 - too much fuel for the amount of air. The control module has already cut fuel as far as it is permitted to and the mixture is still too rich. Left alone, a rich mixture wastes fuel and can foul spark plugs and damage the catalytic converter over time.
Possible causes
- CommonLeaking or stuck-open fuel injector
- CommonFaulty fuel pressure regulator letting pressure run high
- PossibleMass airflow sensor over-reporting airflow
- PossibleFailing oxygen sensor reporting rich incorrectly
- PossibleRestricted air filter starving the engine of air
- PossibleFaulty coolant temperature sensor making the module think the engine is cold
- RareLeaking fuel pressure regulator diaphragm drawing fuel into the intake
What you might notice
- Black smoke from the exhaust
- Strong fuel smell
- Poor fuel economy
- Rough idle
- Spark plugs fouled with soot
- Check engine light on
What to check, in order
- Check the air filter. A heavily restricted filter is the cheapest possible cause and worth eliminating first.
- Watch fuel trim on the live data screen - strongly negative trim confirms the module is cutting fuel to compensate.
- Check the coolant temperature sensor reading against actual engine temperature. A sensor stuck reading cold makes the module enrich the mixture permanently.
- Test fuel pressure. Higher than specification points at the pressure regulator.
- Inspect spark plugs - uniform soot across all of them supports a whole-bank rich condition rather than one bad injector.
- If plugs on one cylinder are much sootier than the rest, suspect that cylinder's injector leaking.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Fuel and air metering
P0100P0101P0102P0103P0104P0105P0106P0107P0108P0109P0110P0111P0112P0113P0114P0115P0116P0117P0118P0119P0120P0121P0122P0123P0124P0125P0126P0127P0128P0129P0130P0131P0132P0133P0134P0135P0136P0137P0138P0139P0140P0141P0142P0143P0144P0145P0146P0147P0148P0149P0150P0151P0152P0153P0154P0155P0156P0157P0158P0159P0160P0161P0162P0163P0164P0165P0166P0167P0168P0169P0170P0171P0172P0173P0174P0175P0176P0177P0178P0179P0180P0181P0182P0183P0184P0185P0186P0187P0188P0189P0190P0191P0192P0193P0194P0195P0196P0197P0198P0199