LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Subaru >> 2022 >> WRX Base, Automatic CVT Trans >> Repair and Diagnosis (Single Page) >> Engine Performance >> System >> Engine Control System (Diagnostics) (4 Of 4) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC P2101: Throttle Actuator "A" Control Motor Circuit Range/Performance >> Notes
April 5, 2026: LEMON Manuals is launched! Read the announcement.

DTC P2101: Throttle Actuator "A" Control Motor Circuit Range/Performance: Notes

1. - 

DTC detecting condition: 

Immediately at fault recognition

Trouble symptom: 

Wiring diagram: 

Engine Electrical System Ref. to WIRING SYSTEM>ENGINE ELECTRICAL SYSTEM

G14614457Courtesy of SUBARU OF AMERICA, INC.
CAUTION:

Use the check board when measuring the ECM terminal voltage and resistance. Ref. to  ENGINE (DIAGNOSTICS) (H4DOTC)>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) (H4DOTC)>BASIC DIAGNOSTIC PROCEDURE>PROCEDURE 

  1. CHECK ELECTRONIC THROTTLE CONTROL RELAY  .
    1. Turn the ignition switch to OFF.
    2. Remove the electronic throttle control relay.
    3. Connect the battery to terminals No. 2 and No. 4 of electronic throttle control relay.
    4. Measure the resistance between electronic throttle control relay terminals.

      Terminals 

      No. 1 - No. 3:

    Is the resistance less than 1 Ω?

    Yes  : Go to  2.

    No  : Replace the electronic throttle control relay. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>ELECTRONIC THROTTLE CONTROL RELAY

  2. CHECK POWER SUPPLY OF ELECTRONIC THROTTLE CONTROL RELAY  .

    Measure the voltage between M/B (electronic throttle control relay) terminal and engine ground.

    Terminals 

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

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

    Is the voltage 10 V or more?

    Yes  : Go to  3.

    No  : Repair the following item.

    • Open circuit or short circuit to ground in harness between M/B (fuse No. 20) and M/B (electronic throttle control relay) terminal
    • Blown out of fuse
  3. CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL RELAY (SHORT TO POWER SUPPLY)  .
    1. Disconnect the connector from ECM.
    2. Turn the ignition switch to ON.
    3. Measure the voltage between M/B (electronic throttle control relay) terminal and engine ground.

      Terminals 

      No. 4 (+) - Engine ground (-):

    Is the voltage 10 V or more?

    Yes  : Repair the short circuit to power in the harness between ECM connector and M/B (electronic throttle control relay) terminal.

    No  : Go to  4.

  4. CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL RELAY (SHORT TO GROUND)  .
    1. Turn the ignition switch to OFF.
    2. Measure the resistance between M/B (electronic throttle control relay) terminal and engine ground.

      Terminals 

      No. 3 - Engine ground:

      No. 4 - Engine ground:

    Is the resistance 1 MΩ or more?

    Yes  : Go to  5.

    No  : Repair the short circuit to ground in the harness between ECM connector and M/B (electronic throttle control relay) terminal.

  5. CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL RELAY (OPEN)  .

    Measure the resistance between ECM connector and M/B (electronic throttle control relay) terminal.

    Connector & terminal 

    (B61) No. 64 - No. 3:

    (B61) No. 60 - No. 4:

    Is the resistance less than 1 Ω?

    Yes  : Go to  6.

    No  : Repair the open circuit in harness between ECM connector and M/B (electronic throttle control relay) terminal.

  6. CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL CONNECTOR (SHORT TO GROUND)  .
    1. Turn the ignition switch to OFF.
    2. Disconnect the connectors from electronic throttle control.
    3. Measure the resistance between the ECM connector and engine ground.

      Connector & terminal 

      (E52) No. 15 - Engine ground:

      (E52) No. 22 - Engine ground:

      (E52) No. 31 - Engine ground:

    Is the resistance 1 MΩ or more?

    Yes  : Go to  7.

    No  : Repair the ground short circuit of harness between ECM connector and electronic throttle control connector.

  7. CHECK SHORT CIRCUIT INSIDE ECM (SHORT TO GROUND)  .
    1. Connect the connector to ECM.
    2. Measure the resistance between electronic throttle control connector and engine ground.

      Connector & terminal 

      (E116) No. 1 - Engine ground:

      (E116) No. 4 - Engine ground:

    Is the resistance 220 kΩ or more?

    Yes  : Go to  8.

    No  : Repair the ground short circuit of harness between ECM connector and electronic throttle control connector. Replace the ECM if defective. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>ENGINE CONTROL MODULE (ECM)

  8. CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL CONNECTOR (OPEN)  .
    1. Disconnect the connector from ECM.
    2. Measure the resistance of harness between ECM connector and electronic throttle control connector.

      Connector & terminal 

      (E52) No. 31 - (E116) No. 1:

      (E52) No. 23 - (E116) No. 3:

      (E52) No. 15 - (E116) No. 4:

    Is the resistance less than 1 Ω?

    Yes  : Go to  9.

    No  : Repair the open circuit of harness between ECM connector and electronic throttle control connector.

  9. CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL CONNECTOR (OPEN)  .
    1. Connect the connector to ECM.
    2. Measure the resistance between electronic throttle control connector and engine ground.

      Connector & terminal 

      (E116) No. 3 - Engine ground:

    Is the resistance less than 5 Ω?

    Yes  : Go to  10.

    No  : Repair the following item.

    • Open circuit of harness between ECM connector and engine ground
    • Poor contact of ECM connector
  10. CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL CONNECTOR (SHORT TO POWER SUPPLY)  .
    1. Turn the ignition switch to ON.
    2. Measure the voltage between electronic throttle control connector and engine ground.

      Connector & terminal 

      (E116) No. 1 (+) - Engine ground (-):

      (E116) No. 4 (+) - Engine ground (-):

    Is the voltage 5 V or more?

    Yes  : Repair the short circuit to power supply in the harness between ECM connector and electronic throttle control connector.

    No  : Go to  11.

  11. CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL CONNECTOR (SHORT BETWEEN LINES)  .
    1. Turn the ignition switch to OFF.
    2. Disconnect the connector from ECM.
    3. Measure the resistance between ECM connectors.

      Connector & terminal 

      (E52) No. 22 - (E52) No. 15:

      (E52) No. 22 - (E52) No. 31:

    Is the resistance 1 MΩ or more?

    Yes  : Go to  12.

    No  : Repair the short circuit between lines in harness between ECM connector and electronic throttle control connector.

  12. CHECK SENSOR OUTPUT  .
    1. Connect all connectors.
    2. Start the engine and warm up completely.
    3. Stop the engine, and then turn the ignition switch to ON (engine OFF).
    4. Using the Subaru Select Monitor, read the value in [Main-Throttle Sensor].
      NOTE:

      For detailed operation procedures, refer to "COMMON (DIAGNOSTICS)". Ref. to  COMMON (DIAGNOSTICS)>DATA MONITOR 

    Is the value of [Main-Throttle Sensor] 0.6 - 0.65 [V]?

    Yes  : Go to  13.

    No  : Repair the poor contact of electronic throttle control connector. Replace the electronic throttle control if defective. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>THROTTLE BODY

  13. CHECK SENSOR OUTPUT  .

    Using the Subaru Select Monitor, read the value in [Sub-Throttle Sensor].

    NOTE:

    For detailed operation procedures, refer to "COMMON (DIAGNOSTICS)". Ref. to  COMMON (DIAGNOSTICS)>DATA MONITOR 

    Is the value of [Sub-Throttle Sensor] 0.6 - 0.65 [V]?

    Yes  : Go to  14.

    No  : Repair the poor contact of electronic throttle control connector. Replace the electronic throttle control if defective. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>THROTTLE BODY

  14. CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL CONNECTOR (OPEN)  .
    1. Turn the ignition switch to OFF.
    2. Disconnect the connector from ECM.
    3. Disconnect the connectors from electronic throttle control.
    4. Measure the resistance between ECM connector and electronic throttle control connector.

      Connector & terminal 

      (E51) No. 29 - (E116) No. 5:

      (E51) No. 30 - (E116) No. 6:

    Is the resistance less than 1 Ω?

    Yes  : Go to  15.

    No  : Repair the open circuit of harness between ECM connector and electronic throttle control connector.

  15. CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL CONNECTOR (SHORT TO POWER SUPPLY)  .
    1. Connect the connector to ECM.
    2. Turn the ignition switch to ON.
    3. Measure the voltage between electronic throttle control connector and engine ground.

      Connector & terminal 

      (E116) No. 5 (+) - Engine ground (-):

      (E116) No. 6 (+) - Engine ground (-):

    Is the voltage 5 V or more?

    Yes  : Repair the short circuit to power supply in the harness between ECM connector and electronic throttle control connector.

    No  : Go to  16.

  16. CHECK HARNESS BETWEEN ECM AND ELECTRONIC THROTTLE CONTROL CONNECTOR (SHORT TO GROUND)  .
    1. Turn the ignition switch to OFF.
    2. Disconnect the connector from ECM.
    3. Measure the resistance between electronic throttle control connector and engine ground.

      Connector & terminal 

      (E116) No. 5 - Engine ground:

      (E116) No. 6 - Engine ground:

    Is the resistance 1 MΩ or more?

    Yes  : Go to  17.

    No  : Repair the ground short circuit of harness between ECM connector and electronic throttle control connector.

  17. CHECK HARNESS FOR ELECTRONIC THROTTLE CONTROL CONNECTOR (SHORT BETWEEN LINES)  .

    Measure the resistance between electronic throttle control connectors.

    Connector & terminal 

    (E116) No. 5 - (E116) No. 6:

    Is the resistance 1 MΩ or more?

    Yes  : Go to  18.

    No  : Repair the short circuit between lines in harness between ECM connector and electronic throttle control connector.

  18. CHECK ELECTRONIC THROTTLE CONTROL GROUND CIRCUIT (OPEN)  .

    Measure the resistance between the ECM connector and engine ground.

    Connector & terminal 

    (B61) No. 47 - Engine ground:

    (B61) No. 48 - Engine ground:

    (B61) No. 63 - Engine ground:

    (E52) No. 2 - Engine ground:

    (E52) No. 10 - Engine ground:

    Is the resistance less than 5 Ω?

    Yes  : Go to  19.

    No  : Repair the following item.

    • Open circuit of harness between ECM connector and engine ground
    • Poor contact of coupling connector
  19. CHECK ELECTRONIC THROTTLE CONTROL  .

    Measure the resistance between electronic throttle control terminals.

    Terminals 

    No. 5 - No. 6:

    Is the resistance 50 Ω or less?

    Yes  : Go to  20.

    No  : Replace the electronic throttle control. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>THROTTLE BODY

  20. CHECK ELECTRONIC THROTTLE CONTROL  .
    1. Move the throttle valve to the fully opened and fully closed positions with fingers.
    2. Check that the valve returns to the specified position when releasing fingers.

    Does the valve return to the specified position? Standard value: 3 mm (0.12 in) from fully closed position

    Yes  : Repair the poor contact of ECM connector.

    No  : Replace the electronic throttle control. Ref. to FUEL INJECTION (FUEL SYSTEMS) (H4DOTC)>THROTTLE BODY

scientia non olet · About LEMON Manuals