DTC P2021: TGV Position Sensor/Switch Circuit Low Bank 2: Notes

DTC detecting condition: 

Immediately at fault recognition

Trouble symptom: 

• Improper idling
• Engine stalls.
• Poor driving performance

Wiring diagram: 

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

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK CURRENT DATA. 
   1. Start the engine.
   2. Read the value of «TGV Position Sensor L» using the Subaru Select Monitor.
   NOTE: For detailed operation procedures, refer to "Current Data Display For Engine". Refer to ENGINE (DIAGNOSTICS) (EXCEPT FOR STI)>SUBARU SELECT MONITOR .

   Is the value of «TGV Position Sensor L» less than 0.2 V?

   Yes:  Go to  2.

   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.
2. CHECK POWER SUPPLY OF TUMBLE GENERATOR VALVE ACTUATOR LH. 
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from tumble generator valve actuator LH.
   3. Turn the ignition switch to ON.
   4. Measure the voltage between tumble generator valve actuator LH connector and engine ground.

      Connector & terminal 

      (E51) No. 3 (+) - Engine ground (-):

   Is the voltage 4.5 V or more?

   Yes:  Go to  3.

   No:  Repair the harness and connector.

   NOTE: In this case, repair the following item:

   • Open circuit in harness between ECM connector and tumble generator valve actuator LH connector
   • Poor contact of ECM connector
3. CHECK HARNESS BETWEEN ECM AND TUMBLE GENERATOR VALVE ACTUATOR LH CONNECTOR. 
   1. Turn the ignition switch to OFF.
   2. Disconnect the connector from ECM.
   3. Measure the resistance of harness between ECM connector and tumble generator valve actuator LH connector.

      Connector & terminal 

      (E158) No. 41 - (E51) No. 1:

   Is the resistance less than 1 Ω?

   Yes:  Go to  4.

   No:  Repair the open circuit in harness between ECM connector and tumble generator valve actuator LH connector.

4. CHECK HARNESS BETWEEN ECM AND TUMBLE GENERATOR VALVE ACTUATOR LH CONNECTOR. 

   Measure the resistance between the ECM connector and engine ground.

   Connector & terminal 

   (E158) No. 41 - 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 tumble generator valve actuator LH connector.

5. CHECK FOR POOR CONTACT. 

   Check for poor contact of ECM and tumble generator valve actuator LH connector.

   Is there poor contact of ECM or the tumble generator valve actuator LH connector?

   Yes:  Repair the poor contact of ECM or tumble generator valve actuator LH connector.

   No:  Replace the tumble generator valve actuator LH. Refer to FUEL INJECTION (FUEL SYSTEMS) (EXCEPT FOR STI)>TUMBLE GENERATOR VALVE ACTUATOR .

   NOTE: The tumble generator valve actuator cannot be disassembled.