DTC P0175 System Too Rich (Bank 2): Trouble Symptom

WARNING: This page is about a different variant/trim than selected.

Improper idling
Engine stalls.
Poor driving performance

CAUTION: After servicing or replacing faulty parts, perform Clear Memory Mode Ref. to OPERATION , Clear Memory Mode, and Inspection Mode Ref. to PROCEDURE , Inspection Mode.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK EXHAUST SYSTEM.	Are there holes or loose bolts on exhaust system?	Repair the exhaust system.	Go to step 2.
2 CHECK AIR INTAKE SYSTEM.	Are there holes, loose bolts or disconnection of hose on air intake system?	Repair the air intake system.	Go to step 3.
3 CHECK FUEL PRESSURE. WARNING: Place "NO OPEN FLAMES" signs near the working area. CAUTION: Be careful not to spill fuel. Measure the fuel pressure. Ref. to INSPECTION , Fuel Pressure. CAUTION: Release fuel pressure before removing the fuel pressure gauge.	Is the measured value 333 - 343 kPa (3.4 - 3.5 kgf/cm² , 48.4 - 49.8 psi)?	Go to step 4.	Repair the following item. Fuel pressure is too high: Clogged fuel line or bent hose Fuel pressure is too low: Improper fuel pump discharge Clogged fuel line
4 CHECK ENGINE COOLANT TEMPERATURE SENSOR. Start the engine and warm up completely. Read the data of engine coolant temperature sensor signal using Subaru Select Monitor or general scan tool. NOTE: Subaru Select Monitor For detailed operation procedures, refer to "READ CURRENT DATA FOR ENGINE". Ref. to SUBARU SELECT MONITOR . General scan tool For detailed operation procedures, refer to the general scan tool operation manual.	Is the temperature 75°C (167°F) or more?	Go to step 5.	Replace the engine coolant temperature sensor. Ref. to ENGINE COOLANT TEMPERATURE SENSOR .
5 CHECK MASS AIR FLOW AND INTAKE AIR TEMPERATURE SENSOR SIGNAL. Start the engine and warm up engine until coolant temperature is higher than 75°C (167°F). Place the select lever in "P" range or "N" range. Turn the A/C switch to OFF. Turn all the accessory switches to OFF. Read the data of mass air flow and intake air temperature sensor signal using Subaru Select Monitor or general scan tool. NOTE: Subaru Select Monitor For detailed operation procedures, refer to "READ CURRENT DATA FOR ENGINE". Ref. to SUBARU SELECT MONITOR . General scan tool For detailed operation procedures, refer to the general scan tool operation manual.	Is the measured value 2.0 - 5.0 g/s (0.26 -0.66 lb/m)?	Go to step 6.	Replace the mass air flow and intake air temperature sensor. Ref. to MASS AIR FLOW AND INTAKE AIR TEMPERATURE SENSOR .
6 CHECK MASS AIR FLOW AND INTAKE AIR TEMPERATURE SENSOR. Start the engine and warm up engine until coolant temperature is higher than 75°C (167°F). Place the select lever in "P" range or "N" range. Turn the A/C switch to OFF. Turn all the accessory switches to OFF. Open the front hood. Measure the ambient temperature. Read the data of mass air flow and intake air temperature sensor signal using Subaru Select Monitor or general scan tool. NOTE: Subaru Select Monitor For detailed operation procedures, refer to "READ CURRENT DATA FOR ENGINE". Ref. to SUBARU SELECT MONITOR . General scan tool For detailed operation procedures, refer to the general scan tool operation manual.	Subtract ambient temperature from intake air temperature. Is the obtained value -10 - 50°C (-18 -90°F)?	Repair the poor contact of ECM connector.	Check the mass air flow and intake air temperature sensor. Ref. to MASS AIR FLOW AND INTAKE AIR TEMPERATURE SENSOR .