P0175 fault code: fuel mixture too rich (Bank 2)
Plain-language definition
System Too Rich Bank 2
What does it mean?
On engines with two banks of cylinders, P0175 is stored for Bank 2, the side without cylinder 1. This bank's mixture is usually monitored by its own oxygen (lambda) sensor; whenever the mixture reads rich, the engine computer cuts the fuel it injects.
The code means the engine computer is struggling to balance the mixture on Bank 2, even though it's cutting the fuel far more than usual. If it shows up together with P0172, a cause affecting both banks comes to mind, such as high fuel pressure or an inaccurate air flow sensor. If it's on its own, an injector or sensor on that bank is the more likely cause.
You may notice higher fuel consumption, a smell of fuel from the exhaust or soot at the tailpipe. When the rich mixture goes on for a long time, the spark plugs can get sooty and the engine may misfire.
How serious is it?
It's rated Warning. Over time the extra fuel can foul the spark plugs and overheat the catalytic converter, damaging it.
Severity is a guide; if the warning light is flashing or you notice symptoms while driving, have the car checked at a workshop.
Common general causes
- Inaccurate air flow sensor (MAF)
- Leaking injectors on this bank
- High fuel pressure (pressure regulator)
- Fuel vapour (canister) valve stuck open
- Temperature sensor showing the engine as cold
- Bank 2 oxygen sensor giving wrong readings
The list shows general causes; a workshop finds the actual cause on your car with a check.
Definitions by make
Some manufacturers record the same code under their own wording:
- BMW
- System Too Rich
- Fiat
- Air / Fuel Ratio (level 2)
Related codes
How does it appear in the 2dakika report?
System Too Rich Bank 2
If the code is read as a confirmed (stored) fault, the report shows it with the "Warning" severity; in pending or past records, codes that don't request the warning light and aren't critical appear as "Info". If the engine computer stored them, the conditions when the fault was recorded (engine temperature, rpm, speed) are shown too.
Read this code with the OBD-X1, and clear it from the app after the repair.
Clearing the code doesn't fix the fault; if the problem persists, the code comes back.