DTC P0023: "B" Camshaft Position Actuator Control Circuit/Open Bank 2: Notes

DTC detecting condition:

Immediately at fault recognition

Trouble symptom:

Improper idling

CAUTION:

After servicing or replacing faulty parts, perform Clear Memory Mode Ref. to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>Clear Memory Mode>OPERATION , and inspection mode Ref. 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 Ref. to WIRING SYSTEM>Engine Electrical System>WIRING DIAGRAM .

Courtesy of SUBARU OF AMERICA, INC.

CHECK OUTPUT SIGNAL OF ECM .
1. Turn the ignition switch to ON.
2. Measure the voltage between ECM connector and engine ground.
  Connector & terminal
  
  (E159) No. 31 (+) - Engine ground (-):
Is the voltage 10 V or more?

Yes: Go to 2

No: Go to 3
CHECK FOR POOR CONTACT .
Check for poor contact of ECM connector.

Is there poor contact of ECM connector?

Yes: Repair the poor contact of ECM connector.

No: Even if DTC is detected, the circuit has returned to a normal condition at this time. Reproduce the failure, and then perform the diagnosis again.

NOTE: In this case, temporary poor contact of connector, temporary open or short circuit of harness may be the cause.
CHECK POWER SUPPLY TO THE EXHAUST OIL CONTROL SOLENOID LH .
Measure the voltage between exhaust oil control solenoid LH connector and engine ground.

Connector & terminal

(E66) No. 1 (+) - Engine ground (-):

Is the voltage 10 V or more?

Yes: Go to 4

No: Repair the power supply circuit.
CHECK HARNESS BETWEEN ECM AND EXHAUST OIL CONTROL SOLENOID LH CONNECTOR .
1. Turn the ignition switch to OFF.
2. Disconnect the connector from ECM.
3. Disconnect the connector from the exhaust oil control solenoid LH.
4. Measure the resistance between exhaust oil control solenoid LH connector and engine ground.
  Connector & terminal
  
  (E66) No. 2 - Engine ground:
Is the resistance 1 MΩ or more?

Yes: Go to 5

No: Repair the short circuit to ground in harness between ECM connector and exhaust oil control solenoid LH connector.
CHECK HARNESS BETWEEN ECM AND EXHAUST OIL CONTROL SOLENOID LH CONNECTOR .
Measure the resistance of harness between ECM connector and exhaust oil control solenoid LH.

Connector & terminal

(E159) No. 31 - (E66) No. 2:

Is the resistance less than 1 Ω?

Yes: Go to 6

No: Repair the harness and connector.
NOTE:
In this case, repair the following item:
- Open circuit in harness between ECM connector and exhaust oil control solenoid LH connector
- Poor contact of coupling connector
CHECK EXHAUST OIL CONTROL SOLENOID LH .
Measure the resistance between exhaust oil control solenoid LH terminals.

Terminals

No. 1 - No. 2:

Is the resistance 6 - 12 Ω?

Yes: Repair the poor contact of exhaust oil control solenoid LH connector.

No: Replace the exhaust oil control solenoid LH. Ref. to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>Oil Control Solenoid .