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Home >> Subaru >> 2017 >> Forester 2.0XT Touring >> Repair and Diagnosis >> Transmission >> Automatic Trans >> Transaxle (Diagnostics) >> Diagnostic Procedure with Diagnostic Trouble Code (DTC) >> DTC P2758 Torque Converter Clutch Pressure Control Solenoid Control Circuit Stuck On >> Notes

DTC P2758 Torque Converter Clutch Pressure Control Solenoid Control Circuit Stuck On: Notes

DTC detecting condition: 

Detected when two consecutive driving cycles with fault occur.

Trouble symptom: 

The engine stalls when the vehicle is stopped.

Wiring diagram: 

Fig 2: Torque Converter Clutch Pressure Control Solenoid Control Circuit Stuck ON System Wiring Diagram (Turbo Model)
G10410243Courtesy of SUBARU OF AMERICA, INC.
  1. CHECK DTC. 

    Read the DTC using Subaru Select Monitor.

    Is any DTC other than DTC P2758 displayed?

    • Yes  : Perform the diagnosis according to DTCs other than P2758.
    • No  : Go to 2. 
  2. CHECK LOCK-UP DUTY SOLENOID (ACTIVE TEST). 
    1. Turn the ignition switch to ON.
    2. Using the Subaru Select Monitor, perform forced operation of the lock-up duty solenoid. Ref. to TRANSMISSION (DIAGNOSTICS)>Active Test .

    Does the indication of 0 → 50% appear repeatedly during forced operation, and does operating sound emit during indicating 50%?

    • Yes  : Go to  8.
    • No  : Go to 3. 
  3. CHECK LOCK-UP DUTY SOLENOID. 
    1. Turn the ignition switch to OFF.
    2. Disconnect the transmission connector.
    3. Measure the resistance between transmission connector and transmission body.

      Connector & terminal 

      Non-turbo model 

      (T4) No. 11 - Transmission body:

      Turbo model 

      (T4) No. 2 - Transmission body:

    Is the resistance approximately 10 - 13.5 Ω? (when cold)

  4. CHECK HARNESS. 
    1. Disconnect the TCM connector.
    2. Measure the resistance between TCM connector and transmission connectors.

      Connector & terminal 

      Non-turbo model 

      (B54) No. 15 - (B11) No. 11:

      Turbo model 

      (B54) No. 15 - (B11) No. 2:

    Is the resistance less than 1 Ω?

    • Yes  : Go to 5. 
    • No  : Repair the open circuit of harness.
  5. CHECK HARNESS. 

    Measure the resistance between TCM connector and transmission body.

    Connector & terminal 

    (B54) No. 15 - Transmission body:

    Is the resistance 1 MΩ or more?

    • Yes  : Go to 6. 
    • No  : Repair the short circuit of harness.
  6. CHECK HARNESS. 
    CAUTION: Start work after ATF cools down.
    1. Remove the following parts.
      • Transmission valve cover (non-turbo model)
      • Transmission oil pan (turbo model)
    2. Disconnect the control valve body connector.
    3. Measure the resistance between transmission connector and control valve body connector.

      Connector & terminal 

      Non-turbo model 

      (T4) No. 11 - (T11) No. 9:

      Turbo model 

      (T4) No. 2 - (T11) No. 2:

    Is the resistance less than 1 Ω?

    • Yes  : Go to 7. 
    • No  : Repair the open circuit of harness.
  7. CHECK HARNESS. 

    Measure the resistance between transmission connector and control valve body connector.

    Connector & terminal 

    Non-turbo model 

    (T11) No. 9 - Control valve body:

    Turbo model 

    (T11) No. 2 - Control valve body:

    Is the resistance 1 MΩ or more?

  8. CHECK TRANSMISSION FLUID. 
    1. Connect all connectors.
    2. Check the amount of ATF. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR580)>CVTF>ADJUSTMENT . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR690)>CVTF>ADJUSTMENT .

    Is the check result OK?

  9. CHECK TRANSMISSION FLUID. 

    Check the condition of ATF. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR580)>CVTF>CONDITION CHECK . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR690)>CVTF>CONDITION CHECK .

    Is the check result OK?

  10. CHECK INPUT SIGNAL FOR TCM. 
    1. Lift up the vehicle.
    2. Start the engine.
    3. Warm up until the ATF temperature reaches to 40 - 70°C (104 - 158°F).
    4. Depress the brake pedal, and shift the select lever to "D" range.
    5. Shift the select lever to "P" range.
    6. Stabilize the engine speed at idle.
    7. Read the data of [Actual Secondary Pressure] using Subaru Select Monitor.

    Is the value of [Actual Secondary Pressure] 0.5 - 1.5 MPa?

  11. DRIVING CHECK FOR LOCK-UP CONDITION. 
    1. Perform the Clear Memory Mode. Ref. to TRANSMISSION (DIAGNOSTICS)>Clear memory .
    2. Turn the ignition switch to OFF.
    3. Start the engine.
    4. Warm up until the ATF temperature exceeds 50°C.
    5. Drive the vehicle for one minute or more while keeping such constant speed that [Lock Up Duty Ratio] is 0%, and [Front Wheel Speed] is 5 km/h (3 MPH) or less, which are displayed on the Subaru Select Monitor.
    6. Turn the ignition switch to OFF.
    7. Start the engine.
    8. Perform the procedure in step 5).
    9. Read the DTC using Subaru Select Monitor.

    Does the AT OIL TEMP light blink and is DTC P2758 displayed? Or does the engine stall?

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