Subaru Legacy BN/BS (2015-2019) Service Manual: General diagnostic table inspection

1. Engine stalls during idling.

1) Manifold absolute pressure sensor

2) Mass air flow and intake air temperature sensor

3) Ignition parts (*1)

4) Engine coolant temperature sensor (*2)

5) Crankshaft position sensor (*3)

6) Camshaft position sensor (*3)

7) Fuel injection parts (*4)

8) Electronic throttle control

2. Rough idling

1) Manifold absolute pressure sensor

2) Mass air flow and intake air temperature sensor

3) Engine coolant temperature sensor (*2)

4) Ignition parts (*1)

5) Air intake system (*5)

6) Fuel injection parts (*4)

7) Electronic throttle control

8) Crankshaft position sensor (*3)

9) Camshaft position sensor (*3)

10) Oxygen sensor

11) Fuel pump and fuel pump relay

12) EGR control valve

3. Engine does not return to idle.

1) Engine coolant temperature sensor

2) Electronic throttle control

3) Manifold absolute pressure sensor

4) Mass air flow and intake air temperature sensor

5) EGR control valve

6) Accelerator pedal position sensor

7) Engine oil temperature sensor

4. Poor acceleration

1) Manifold absolute pressure sensor

2) Mass air flow and intake air temperature sensor

3) Electronic throttle control

4) Fuel injection parts (*4)

5) Fuel pump and fuel pump relay

6) Engine coolant temperature sensor (*2)

7) Crankshaft position sensor (*3)

8) Camshaft position sensor (*3)

9) Engine torque control signal circuit

10) Ignition parts (*1)

11) EGR control valve

12) Accelerator pedal position sensor

13) Engine oil temperature sensor

5. Engine stalls, hesitates, or sputters at acceleration.

1) Manifold absolute pressure sensor

2) Mass air flow and intake air temperature sensor

3) Engine coolant temperature sensor (*2)

4) Crankshaft position sensor (*3)

5) Camshaft position sensor (*3)

6) Purge control solenoid valve

7) Fuel injection parts (*4)

8) Electronic throttle control

9) Fuel pump and fuel pump relay

10) EGR control valve

6. Surging

1) Mass air flow and intake air temperature sensor

2) Manifold absolute pressure sensor

3) Engine coolant temperature sensor (*2)

4) Crankshaft position sensor (*3)

5) Camshaft position sensor (*3)

6) Fuel injection parts (*4)

7) Electronic throttle control

8) Fuel pump and fuel pump relay

9) EGR control valve

7. Spark knock

1) Mass air flow and intake air temperature sensor

2) Manifold absolute pressure sensor

3) Engine coolant temperature sensor

4) Knock sensor

5) Fuel injection parts (*4)

6) Fuel pump and fuel pump relay

7) EGR control valve

8. After burning in exhaust system

1) Mass air flow and intake air temperature sensor

2) Manifold absolute pressure sensor

3) Engine coolant temperature sensor (*2)

4) Fuel injection parts (*4)

5) Fuel pump and fuel pump relay