DTC P0175 System Too Rich (Bank 2)

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

DTC DETECTING CONDITION:

Two consecutive driving cycles with fault
GENERAL DESCRIPTION < Ref. to DTC P0171 SYSTEM TOO LEAN (BANK 1) , Diagnostic Trouble Code (DTC) Detecting Criteria.> < Ref. to DTC P0172 SYSTEM TOO RICH (BANK 1) , Diagnostic Trouble Code (DTC) Detecting Criteria.> and < Ref. to DTC P0174 SYSTEM TOO LEAN (BANK 2) , Diagnostic Trouble Code (DTC) Detecting Criteria.> < Ref. to DTC P0175 SYSTEM TOO RICH (BANK 2) , Diagnostic Trouble Code (DTC) Detecting Criteria. >

TROUBLE SYMPTOM:

Erroneous idling
Engine stalls.
Poor driving performance

CAUTION: After repair or replacement of faulty parts, conduct Clear Memory Mode < Ref. to , OPERATION , Clear Memory Mode.> and Inspection Mode < Ref. to , OPERATION , Inspection Mode.>.

DTC P0175 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 FIRE" signs near the working area. Be careful not to spill fuel on the floor. Release the fuel pressure. Disconnect the connector from fuel pump relay. Start the engine and run it until it stalls. After the engine stalls, crank it for 5 more seconds. Turn the ignition switch to OFF. Connect the connector to fuel pump relay. Disconnect the fuel delivery hose from fuel filter, and connect fuel pressure gauge. Install the fuel filler cap. Start the engine and idle while gear position is neutral. Measure the fuel pressure while disconnecting pressure regulator vacuum hose from intake manifold. WARNING: Before removing the fuel pressure gauge, release fuel pressure. NOTE: If the fuel pressure does not increase, squeeze fuel return hose 2 to 3 times, then measure fuel pressure again.	Is the measured value 284 - 314 kPa (2.9 - 3.2 kg/cm² , 41 - 46 psi)?	Go to step 4.	Repair the following items. Fuel pressure too high: Clogged fuel return line or bent hose Fuel pressure too low: Improper fuel pump discharge Clogged fuel supply line
4. CHECK FUEL PRESSURE. After connecting the pressure regulator vacuum hose, measure fuel pressure. WARNING: Before removing the fuel pressure gauge, release fuel pressure. NOTE: If the fuel pressure does not increase, squeeze fuel return hose 2 to 3 times, then measure fuel pressure again. If out of specification as measured at this step, check or replace the pressure regulator and pressure regulator vacuum hose.	Is the measured value 206 - 235 kPa (2.1 - 2.4 kg/cm² , 30 - 34 psi)?	Go to step 5.	Repair the following items. Fuel pressure too high: Faulty pressure regulator Clogged fuel return line or bent hose Fuel pressure too low: Faulty pressure regulator Improper fuel pump discharge Clogged fuel supply line
5. 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 OBD-II general scan tool. NOTE: Subaru Select Monitor For detailed operation procedure, refer to the "READ CURRENT DATA FOR ENGINE". < Ref. to , SUBARU SELECT MONITOR . > OBD-II general scan tool For detailed operation procedure, refer to the OBD-II general scan tool instruction manual .	Is the temperature more than 60°C (140°F)?	Go to step 6.	Replace the engine coolant temperature sensor. < Ref. to ENGINE COOLANT TEMPERATURE SENSOR . >
6. CHECK MASS AIR FLOW AND INTAKE AIR TEMPERATURE. Start the engine and warm-up engine until coolant temperature is greater than 60°C (140°F). Place the shift lever in neutral position. Turn the A/C switch to OFF. Turn all accessory switches to OFF. Read the data of mass air flow and intake air temperature sensor signal using Subaru Select Monitor or OBD-II general scan tool. NOTE: Subaru Select Monitor For detailed operation procedure, refer to the "READ CURRENT DATA FOR ENGINE". < Ref. to , SUBARU SELECT MONITOR . > OBD-II general scan tool For detailed operation procedure, refer to the OBD-II general scan tool instruction manual .	Is the measured value within the followings? Ignition ON: 73.3 - 106.6 kPa (550 - 800 mmHg, 21.65 - 31.50 inHg) Idling: 24.0 - 41.3 kPa (180 - 310 mmHg, 7.09 - 12.20 inHg)	Go to step 7.	Replace the mass air flow and intake air temperature sensor. < Ref. to MASS AIR FLOW AND INTAKE AIR TEMPERATURE SENSOR . >
7. CHECK MASS AIR FLOW AND INTAKE AIR TEMPERATURE SENSOR. Start the engine and warm-up engine until coolant temperature is greater than 60°C (140°F). Place the shift lever in neutral position. Turn the A/C switch to OFF. Turn all 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 OBD-II general scan tool. NOTE: Subaru Select Monitor For detailed operation procedure, refer to the "READ CURRENT DATA FOR ENGINE". < Ref. to , SUBARU SELECT MONITOR . > OBD-II general scan tool For detailed operation procedure, refer to the OBD-II general scan tool instruction manual .	Subtract ambient temperature from intake air temperature. Is the obtained value -10°C - 50°C (14°F- 122°F)?	Contact your SOA Service Center.	Check the mass air flow and intake air temperature sensor. < Ref. to MASS AIR FLOW AND INTAKE AIR TEMPERATURE SENSOR . >