LEMON Manuals: Even more car manuals for everyone
Home >> Subaru >> 2019 >> WRX STI Limited >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 2 (Continuously Variable Transmission (Diagnostics)) >> Diagnostic Procedure With Diagnostic Trouble Code (DTC) >> DTC P0966: Pressure Control Solenoid "B" Control Circuit Low >> Notes

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

WARNING: This page is about a different variant/trim than selected.

DTC detecting condition: 

Immediately at fault recognition

Trouble symptom: 

Excessive shift shock

CAUTION: Use the check board when measuring the TCM terminal voltage and resistance.

Wiring diagram: 

CVT control system Refer to WIRING SYSTEM>CVT CONTROL SYSTEM .

G10268531Courtesy of SUBARU OF AMERICA, INC.
  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. Read the data of «Commanded Forward & Reverse Linear Solenoid Current» and «Actual Forward & Reverse Linear Solenoid Current» using Subaru Select Monitor.

    Does the value of «Commanded Forward & Reverse Linear Solenoid Current» and «Actual Forward & Reverse Linear Solenoid Current» almost correspond?

    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 

    (T4) No. 9 - Transmission body:

    Is the resistance approx. 4 - 6 Ω? (when cold)

    Yes:  Check for poor contact of connector, and if no fault is found, replace the TCM. Refer 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 transmission oil pan.
    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 

      (T4) No. 9 - Transmission body:

    Is the resistance 1 MΩ or more?

    Yes:  Replace the control valve body. Refer to CONTINUOUSLY VARIABLE TRANSMISSION (TR690)>CONTROL VALVE BODY .

    No:  Replace the transmission harness.