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

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

1. -

DTC detecting condition:

Immediately at fault recognition

Trouble symptom:

Improper idling
Engine stall
Poor driving performance

Wiring diagram:

Engine Electrical System Ref. to WIRING SYSTEM (IMPREZA MODEL)>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM . Ref. to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>ENGINE ELECTRICAL SYSTEM>WIRING DIAGRAM .

IMPREZA MODEL

Courtesy of SUBARU OF AMERICA, INC.

CROSSTREK MODEL

Courtesy of SUBARU OF AMERICA, INC.

CAUTION: Use the check board when measuring the ECM terminal voltage and resistance. Ref. to ENGINE (DIAGNOSTICS) (H4DO 2.0 (EXCEPT FOR HEV))>GENERAL DESCRIPTION>PREPARATION TOOL>HOW TO USE CHECK BOARD .

NOTE: After the faulty parts are repaired or replaced, perform the final check in Basic Diagnostic Procedure. Ref. to ENGINE (DIAGNOSTICS) (H4DO 2.0 (EXCEPT FOR HEV))>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE .

CHECK DATA MONITOR .
1. Start the engine.
2. Using the Subaru Select Monitor, read the value in [TGV Position Sensor L].
NOTE: For detailed operation procedures, refer to "Common (Diagnostics)". Ref. to COMMON (DIAG)>DATA MONITOR .

Is the value in [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.
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 and 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
CHECK HARNESS BETWEEN ECM AND TUMBLE GENERATOR VALVE ACTUATOR LH (OPEN) .
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 and terminal

(E158) No. 42 - (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.
CHECK HARNESS BETWEEN ECM AND TUMBLE GENERATOR VALVE ACTUATOR LH (SHORT TO GROUND) .
Measure the resistance between the ECM connector and engine ground.

Connector and terminal

(E158) No. 42 - 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.
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. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DO (EXCEPT FOR HEV))>TUMBLE GENERATOR VALVE ACTUATOR .

NOTE: The tumble generator valve actuator cannot be disassembled.