DTC P0973: Shift Solenoid "A" Control Circuit Low: Notes

WARNING: This page is about a different car, the 2020 Subaru Impreza. However, it is still accessible from the selected car via links, so may be relevant.

1. -

DTC detecting condition:

Immediately at fault recognition

Trouble symptom:

Gear is not changed. (No up-shift)

Wiring diagram:

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

Courtesy of SUBARU OF AMERICA, INC.

CAUTION:

Use CHECK BOARD when measuring the TCM terminal voltage and resistance.
After servicing or replacing faulty parts, perform the last step of the basic diagnostic procedure. Ref. to TRANSMISSION (DIAGNOSTICS) (IMPREZA MODEL)>BASIC DIAGNOSTIC PROCEDURE .

Courtesy of SUBARU OF AMERICA, INC.

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 chassis ground.
  Connector & terminal
  
  (T10) No. 47 - Chassis ground:
Is the resistance 1 MΩ or more?

Yes : Go to 2.

No : Repair the short circuit of harness.
CHECK PRIMARY UP SOLENOID .
1. Connect the connector for control valve body.
2. Measure the resistance between TCM connector and transmission body.
  Connector & terminal
  
  (T10) No. 47 - 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 IMPREZA)>TRANSMISSION CONTROL MODULE (TCM) .

No : Go to 3.
CHECK HARNESS INSIDE TRANSMISSION .
Check for the harness pinch, damage.

Is there any fault in the harness?

Yes : Replace the transmission harness.

No : Replace the control valve body. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580 IMPREZA)>CONTROL VALVE BODY .