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

1. - 

DTC detecting condition: 

Detected when two consecutive driving cycles with fault occur.

Trouble symptom: 

The engine stalls when the vehicle is stopped.

Wiring diagram: 

CVT control system Ref. to WIRING SYSTEM (IMPREZA MODEL)>CVT CONTROL SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK DTC  .

   Read the DTC of [Transmission] using the Subaru Select Monitor. Ref. to TRANSMISSION (DIAGNOSTICS) (IMPREZA MODEL)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is a DTC other than DTC P2758 displayed?

   Yes:  Go to  3

   No:  Go to  2.

2. CHECK LOCK-UP DUTY SOLENOID (ACTIVE TEST)  .

   Read the DTC of [Transmission] using the Subaru Select Monitor. Ref. to TRANSMISSION (DIAGNOSTICS) (IMPREZA MODEL)>DIAGNOSTIC TROUBLE CODE (DTC) .

   Is DTC P2763 or P2764 displayed?

   Yes:  Perform the diagnosis according to DTC P2763 or P2764. Ref. to TRANSMISSION (DIAGNOSTICS) (IMPREZA MODEL)>DIAGNOSTIC TROUBLE CODE (DTC)>LIST .

   No:  Go to  3.

3. CHECK LOCK-UP DUTY SOLENOID (ACTIVE TEST)  .
   1. Turn the ignition switch to ON.
   2. Using the Subaru Select Monitor, perform the active test of the lock-up duty solenoid. Ref. to Active Test .

   Does the indication of 0 ? 50% appear repeatedly during the active test, and does operating sound emit during indicating 50%?

   Yes:  Go to  7.

   No:  Go to  4.

4. CHECK LOCK-UP DUTY SOLENOID  .
   1. Remove the transmission valve cover.
   2. Disconnect the control valve body connector.
   3. Measure the resistance between TCM connector and control valve body connector.

      Connector & terminal 

      (T10) No. 15 - Transmission body:

   Is the resistance less than 1 Ω?

   Yes:  Repair the control valve body. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR580 IMPREZA)>CONTROL VALVE BODY .

   No:  Go to  5.

5. CHECK HARNESS  .
   CAUTION:

   Start work after ATF cools down. 

   1. Remove the transmission valve cover.
   2. Disconnect the control valve body connector.
   3. Measure the resistance between TCM connector and control valve body connector.

   Measure the resistance between TCM connector and transmission body.

   Connector & terminal 

   (T10) No. 15 - (T11) No. 9:

   Is the resistance less than 1 Ω?

   Yes:  Go to  6.

   No:  Repair the short circuit of harness.

6. CHECK HARNESS  .

   Measure the resistance between TCM connector and transmission body.

   Connector & terminal 

   (T10) No. 15 - Control valve body:

   Is the resistance 1 MΩ or more?

   Yes:  Replace the control valve body. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR580 IMPREZA)>CONTROL VALVE BODY .

   No:  Repair the short circuit of harness.

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

   Is the check result OK?

   Yes:  Go to  10.

   No:  Adjust the amount of ATF. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR580 IMPREZA)>CVTF>ADJUSTMENT . Go to  8.

8. CHECK TRANSMISSION FLUID  .

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

   Is the check result OK?

   Yes:  Return ATF. Go to  9.

   No:  Check according to the "Corrective action" of ATF (CVTF) "CONDITION CHECK". Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR580 IMPREZA)>CVTF>CONDITION CHECK .

9. CHECK ENGAGEMENT CONDITION OF LOCK-UP CLUTCH  .
   1. Start the engine.
   2. Warm up until the ATF temperature exceeds 50°C (122°F).
   3. Depress the brake pedal, and shift the select lever to "D" range.

   Are there any vibrations due to engine stall or engine speed drop?

   Yes:  Replace the control valve body. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR580 IMPREZA)>CONTROL VALVE BODY .

   No:  Go to  10.

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. Set the select lever to "D" range.
    5. Drive at vehicle speed of 2 km/h (1.25 MPH) or more.
    6. Shift the select lever to "P" range.
    7. Stabilize the engine speed at idle.
    8. Using the Subaru Select Monitor, read data of [Actual Secondary Pressure] in the [Data Monitor] of [Transmission]. Ref. to TRANSMISSION (DIAGNOSTICS) (IMPREZA MODEL)>DATA MONITOR .

    Is [Actual Secondary Pressure] 0.5 - 1.5 MPa?

    Yes:  Replace the control valve body. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580 IMPREZA)>CONTROL VALVE BODY . Go to  11.

    No:  Perform the diagnosis according to DTC P0841. Ref. to TRANSMISSION (DIAGNOSTICS) (IMPREZA MODEL)>DIAGNOSTIC PROCEDURE WITH DIAGNOSTIC TROUBLE CODE (DTC)>DTC P0841 TRANSMISSION FLUID PRESSURE SENSOR/SWITCH "A" CIRCUIT RANGE/PERFORMANCE .

11. DRIVING CHECK FOR LOCK-UP CONDITION  .
    1. Using the Subaru Select Monitor, perform the clear memory of [Transmission]. Ref. to COMMON (DIAG)>CLEAR MEMORY .
    2. Turn the ignition switch to OFF.
    3. Start the engine.
    4. Warm up until the ATF temperature exceeds 50°C.
    5. Depress the brake pedal, and shift the select lever to "D" range.
    6. Shift the select lever to "P" range.
    7. Turn the ignition switch to OFF.
    8. Start the engine.
    9. Perform the procedure in step  5 again.
    10. Read the DTC of [Transmission] using the Subaru Select Monitor. Ref. to TRANSMISSION (DIAGNOSTICS) (IMPREZA MODEL)>DIAGNOSTIC TROUBLE CODE (DTC) .

    Does the AT OIL TEMP light blink and is DTC P2758 displayed? Or are there any vibrations due to engine stall or engine speed drop?

    Yes:  Replace the torque converter assembly, and perform step 11  again. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580 IMPREZA)>CONTROL VALVE BODY . If the replacement of the torque converter assembly does not eliminate the malfunction, replace the transmission assembly and perform step 11 again. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR580 IMPREZA)>AUTOMATIC TRANSMISSION ASSEMBLY .

    No:  Current condition is normal. It is possible that temporary failure occurred.