P0175

What P0175 means

This code means the oxygen sensors on Bank 2 (the side of the engine that does not have cylinder 1) are telling the computer there's too much fuel and not enough air in the exhaust, more of the time than the computer allows for. It's a rich condition. This isn't a code that names a broken part. It's the computer describing a symptom it's seeing downstream, and there's more than one thing upstream that can cause it.

Is it safe to drive

Generally yes, for a while. A rich-running engine wastes fuel and can eventually foul spark plugs or damage the catalytic converter if it goes on long enough, but it's not something that strands you today. Watch for a smell of raw fuel from the exhaust, rough idle, sluggish acceleration, or the check engine light starting to blink or flash, which means the misfire is severe enough to hurt the catalytic converter faster. If any of that shows up, get it looked at sooner rather than later.

Common causes, most likely first

A failing oxygen sensor or a wiring problem at the sensor connector is common and one of the cheaper fixes. A leaking or stuck-open fuel injector on Bank 2 is another frequent cause, and on V6 or V8 engines it can be just one injector out of several. A weak fuel pressure regulator that's letting too much fuel pressure build can do it too. Less commonly, a dirty or failing mass airflow sensor misreports how much air is coming in, which throws off the fuel trim even though the injectors and sensors are fine. On some engines, a bad PCV valve or a stuck-closed EGR can also push the mixture rich. Which of these is likely depends on the engine and how many miles are on it, and on some V-configuration engines it's worth knowing that Bank 2's parts are physically harder to reach than Bank 1's, which affects labor time more than the diagnosis itself.

What diagnosis and repair involve

Diagnosis starts with pulling live fuel trim data and freeze frame information, then checking the Bank 2 oxygen sensor's actual readings, fuel pressure, and injector performance before anything gets replaced. That's typically an hour or so of diagnostic time. If it turns out to be an oxygen sensor, that's a comparatively small repair. A fuel injector or a set of injectors costs more, and if the pressure regulator or mass airflow sensor is the culprit, that changes the parts list too. We wouldn't want to quote a number without seeing which one it actually is, since guessing here is how people end up buying a part that doesn't fix the problem. Auto Star Service Center is open Saturdays, 8 to 6, if getting it checked during the week isn't practical.