DTC P0966 Pressure Control Solenoid "B" Control Circuit Low: Notes

DTC detecting condition: 

Immediately at fault recognition

Trouble symptom: 

Excessive shift shock

Wiring diagram: 

• Non-turbo model

  CVT control system Ref. to WIRING SYSTEM>CVT Control System>WIRING DIAGRAM>NON-TURBO MODEL .

  Fig 1: Pressure Control Solenoid (B) Control Circuit Low System Wiring Diagram (Non-Turbo Model)

  Courtesy of SUBARU OF AMERICA, INC.
• Turbo model

  CVT control system Ref. to WIRING SYSTEM>CVT Control System>WIRING DIAGRAM>TURBO MODEL .

1. CHECK INPUT SIGNAL FOR TCM. 
   1. After driving with warm up condition, park the vehicle while depressing the brake pedal at "D" range.
   2. Using Subaru Select Monitor, read the data of [Commanded Forward & Reverse Linear Solenoid Current] and [Actual Forward & Reverse Linear Solenoid Current].

   Do [Commanded Forward & Reverse Linear Solenoid Current] and [Actual Forward & Reverse Linear Solenoid Current] almost match?

   • Yes  : Check for poor contact of connector.
   • No  : Go to 2. 
2. CHECK HARNESS. 
   1. Turn the ignition switch to OFF.
   2. Disconnect the TCM connector.
   3. Disconnect the transmission connector.
   4. Measure the resistance between TCM connector and chassis ground.

      Connector & terminal 

      (B54) No. 16 - Chassis ground:

   Is the resistance 1 MΩ or more?

   • Yes  : Go to 3. 
   • No  : Repair the short circuit of harness.
3. CHECK F&R SOLENOID. 

   Measure the resistance between transmission connector and transmission body.

   Connector & terminal 

   Non-turbo model 

   (T4) No. 7 - Transmission body:

   Turbo model 

   (T4) No. 9 - Transmission body:

   Is the resistance approximately 4 - 6 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)>Transmission Control Module (TCM) . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR690)>Transmission Control Module (TCM) .
   • No  : Go to 4. 
4. CHECK HARNESS INSIDE TRANSMISSION. 
   CAUTION: Start work after ATF cools down.
   1. Remove the following parts.
      • Transmission valve cover (non-turbo model)
      • Transmission oil pan (turbo model)
   2. Check for the harness pinch, damage.

   Is there any fault in the harness?

   • Yes  : Replace the transmission harness.
   • No  : Go to 5. 
5. CHECK HARNESS INSIDE TRANSMISSION. 
   1. Disconnect the control valve body connector.
   2. Measure the resistance between transmission connector and transmission body.

      Connector & terminal 

      Non-turbo model 

      (T4) No. 7 - Transmission body:

      Turbo model 

      (T4) No. 9 - Transmission body:

   Is the resistance 1 MΩ or more?

   • Yes  : Replace the control valve body. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR580)>Control Valve Body . Ref. to CONTINUOUSLY VARIABLE TRANSMISSION(TR690)>Control Valve Body .
   • No  : Replace the transmission harness.