DTC P0977: Shift Solenoid "B" Control Circuit High: Notes

1. - 

DTC detecting condition: 

Immediately at fault recognition

Trouble symptom: 

Gear is not changed. (No down-shift)

Wiring diagram: 

CVT control system Ref. to WIRING SYSTEM (CROSSTREK MODEL (EXCEPT FOR HEV))>CVT CONTROL SYSTEM .

Courtesy of SUBARU OF AMERICA, INC.

Courtesy of SUBARU OF AMERICA, INC.

1. CHECK HARNESS  .
   CAUTION: Start work after ATF cools down.
   1. Turn the ignition switch to OFF.
   2. Disconnect the TCM connector.
   3. Remove the transmission valve cover.
   4. Disconnect the control valve body connector.
   5. Measure the resistance between TCM connector and control valve body connector.

      Connector & terminal 

      (T10) No. 30 - (T11) No. 7:

   Is the resistance less than 1 Ω?

   Yes  : Go to  2.

   No  : Repair the open circuit of harness.

2. CHECK HARNESS  .
   1. Turn the ignition switch to ON.
   2. Measure the voltage between TCM connector and chassis ground.

      Connector & terminal 

      (T10) No. 30 (+) - Chassis ground (-):

   Is the voltage approx. 0 V?

   Yes  : Go to  3.

   No  : Repair the short circuit of harness.

3. CHECK PRIMARY DOWN SOLENOID  .
   1. Connect the connector for control valve body.
   2. Measure the resistance between TCM connector and transmission body.

      Connector & terminal 

      (T10) No. 30 - Transmission body:

   Is the resistance approximately 10 - 14.2 Ω? (When cold)

   Yes  : Check for poor contact of connector, and if no fault is found, replace the TCM. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580 CROSSTREK)>TRANSMISSION CONTROL MODULE (TCM) .

   No  : Go to  4.

4. CHECK HARNESS INSIDE TRANSMISSION  .

   Check for the harness pinch, damage.

   Is the check result OK?

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

   No  : Replace the transmission harness.