P0175 — System Too Rich (Bank 2)

What it means

The control module has cut long-term fuel trim on bank 2 to its lower limit because the mixture on that bank contains too much fuel. Bank 2 is the cylinder bank without cylinder 1, so the code occurs on V-type and boxer engines only. Excess fuel sooted the spark plugs, dilutes the engine oil and overheats the catalytic converter of that bank.

Likely causes (most common first)

1. Leaking injectors on bank 2 that do not close tightly
2. Excessive fuel pressure from a faulty regulator or a restricted return line, which usually affects both banks
3. Faulty upstream oxygen sensor on bank 2 permanently reporting a lean mixture
4. Mass air flow sensor overreporting airflow, or a faulty coolant temperature sensor keeping the warm-up enrichment active
5. Clogged air filter or restricted exhaust on that bank reducing the amount of air
6. Purge valve stuck open, feeding fuel vapour from the carbon canister into the intake

Can you drive with it?

You can still drive, but the excess fuel destroys the catalytic converter and dilutes the oil, so plan the repair for the next few days.