P0175 Subaru Outback
System Too Rich (Bank 2) · Powertrain Code · Medium · Repair: Moderate
What is P0175?
The engine is running rich on bank 2. Same causes as P0172 but affecting the opposite cylinder bank.
When the Subaru Outback triggers code P0175 (system too rich (bank 2)), it typically points to an issue in the powertrain system. Below you'll find the most common causes, symptoms, and repair options specific to the Subaru Outback.
This repair is rated moderate, meaning some experience and specialty tools required.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Subaru Outback.
Common Causes on Subaru Outback
- MAF sensor contamination affecting Bank 2 readings (H6 boxer engines)
- Vacuum leak on Bank 2 intake runner
- Leaking fuel injector on Bank 2
- Restricted air filter
- Fuel pressure regulator failure
Symptoms
- Check Engine Light on
- Rich exhaust smell
- Poor fuel economy
- Rough running on Bank 2
- Fouled Bank 2 spark plugs
Notes for Subaru Outback
P0175 only applies to H6 (6-cylinder) Subaru models; 4-cylinder boxer engines only set P0172 for rich conditions.