DTC P0390: Camshaft Position Sensor "B" Circuit Bank 2: Notes

DTC detecting condition: 

Immediately at fault recognition

Trouble symptom: 

• Engine stalls.
• Failure of engine to start
  CAUTION:

  • After servicing or replacing faulty parts, perform Clear Memory Mode Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>CLEAR MEMORY MODE>OPERATION , and inspection mode Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>INSPECTION MODE>PROCEDURE ..
  • Use the check board when measuring the ECM terminal voltage and resistance.

Wiring diagram: 

Engine Electrical System Refer to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK POWER SUPPLY OF CAMSHAFT POSITION SENSOR LH. 
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from camshaft position sensor LH.
   3. Turn the ignition switch to ON.
   4. Measure the voltage between camshaft position sensor LH connector and engine ground.

      Connector & terminal 

      (E65) No. 1 (+) - Engine ground (-):

   Is the voltage 10 V or more?

   Yes:  Go to  2.

   No:  Repair the harness and connector.

   NOTE: In this case, repair the following item:

   • Open circuit or short circuit to ground in harness between main relay connector and camshaft position sensor LH connector
   • Poor contact of coupling connector
2. CHECK HARNESS BETWEEN ECM AND CAMSHAFT POSITION SENSOR LH CONNECTOR. 
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from ECM.
   3. Measure the resistance between ECM connector and camshaft position sensor LH connector.

      Connector & terminal 

      (E158) No. 33 - (E65) No. 2:

      (E158) No. 34 - (E65) No. 3:

   Is the resistance less than 1 Ω?

   Yes:  Go to  3.

   No:  Repair the open circuit in the harness between the ECM connector and camshaft position sensor LH connector.

3. CHECK HARNESS BETWEEN ECM AND CAMSHAFT POSITION SENSOR LH CONNECTOR. 

   Measure the resistance between camshaft position sensor LH connector and engine ground.

   Connector & terminal 

   (E65) No. 2 - Engine ground:

   Is the resistance 1 MΩ or more?

   Yes:  Go to  4.

   No:  Repair the short circuit to ground in the harness between the ECM connector and camshaft position sensor LH connector.

4. CHECK HARNESS BETWEEN ECM AND CAMSHAFT POSITION SENSOR LH CONNECTOR. 

   Measure the voltage between camshaft position sensor LH connector and engine ground.

   Connector & terminal 

   (E65) No. 2 (+) - Engine ground (-):

   Is the voltage 5 V or more?

   Yes:  Repair the short circuit to power supply in the harness between the ECM connector and camshaft position sensor LH connector.

   No:  Go to  5.

5. CHECK CONDITION OF CAMSHAFT POSITION SENSOR LH. 

   Check installation condition of the camshaft position sensor LH.

   Is the camshaft position sensor LH installation bolt tightened securely?

   Yes:  Go to  6.

   No:  Tighten the camshaft position sensor LH installation bolt securely. Refer to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>CAMSHAFT POSITION SENSOR>INSTALLATION .

6. CHECK CAMSHAFT POSITION SENSOR LH. 

   Check the waveform of the camshaft position sensor LH. Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>ENGINE CONTROL MODULE (ECM) I/O SIGNAL .

   Is there any abnormality in waveform?

   Yes:  Replace the camshaft position sensor LH. Refer to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>CAMSHAFT POSITION SENSOR .

   No:  Repair the following item.

   • Poor contact of ECM connector
   • Poor contact of camshaft position sensor LH connector
   • Poor contact of coupling connector