A common trouble code with the Subaru Outback is P0175. This code number references a number that is given to you when you plug a vehicle into an OBDII scanner. It’s not the most complicated OBDII trouble code to diagnose. It is also one of the most common. It means that the motor is running with a rich condition.
Outback P0175 Code Defined
P0175 is thrown when the oxygen sensors detect that the air fuel mixture is too rich. Bank 2 refers to the rich condition being detected on the side of the engine with cylinder two.
Outback P0175 Code Symptoms
The P0175 code on a Subaru Outback will often be thrown if the fuel injection system is not operating properly. Typically the code will be triggered by a rich condition in the engine.
There aren’t usually any drivability issues associated with P0175. For most people the first sign that anything is wrong at all is the service engine soon light coming on.
Here are the typical symptoms that something is wrong when you have code P0175.
- Mileage- may or may not suffer depending on how much the air fuel mixture has changed.
- Misfire– If the air fuel mixture has gotten too far from factory specs, this can cause the Outback to misfire.
- Idle Issues– With the air/fuel mixture altered, the vehicle can idle erratically as the computer compensates to keep the engine running.
- Exhaust Smell/Color– Depending on how rich the motor is running, there could be some exhaust odor or discoloration.
- Fouled Spark Plugs– The spark plugs can foul if the engine runs very rich for a long enough period of time.
This youtube video is a great resource for diagnosing the P0175 trouble code in your Outback.
Top Subaru Outback P0175 Causes
Here are the most common causes of P0175:
- Vacuum Leaks– With the Subaru Outback, one of the most common cause for the P0175 code to be thrown is a vacuum leak. Take a look around and see if you can find the vacuum leak. Here’s a great YouTube video on how to find a vacuum leak.
- O2 Sensor– The P0175 codes is thrown when the oxygen sensor(s) do not register the right amount of oxygen in the exhaust. When the oxygen sensor is bad, it can cause a false reading and trigger the code. The computer will still adjust the air/fuel mixture to compensate. This will cause the Outback to run rich. Subaru Outback O2 Sensor
- Mass Air Flow Sensor– The mass air flow sensor calculates the volume of air entering the engine. If it has gone bad, the air fuel mixture will be off and the P0175 code will show.
- Bad Fuel Injectors– If you have one or more fuel injectors that have gone bad that can certainly cause the air/fuel mixture to go bad.
- Fuel Pump/Fuel Filter– Today’s modern fuel injected motors need a lot of fuel pressure to atomize the gas properly. If the fuel pressure is off, atomization doesn’t happen properly and the optimal air/fuel mixture isn’t achieved.
- Air Filter– While it’s not the most common reason to throw the P0175 code, a clogged air filter certainly can cause the code to throw. And, since it’s so easy to check, why not take a look?
Good luck figuring out what is wrong with your Outback. If there is anything that you feel could improve the article, please feel free to comment or message. Thank you.