DTC P0712: Transmission Fluid Temperature Sensor "A" 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:

Excessive shift shock
Shift characteristics malfunction

Wiring diagram:

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

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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 .
1. Turn the ignition switch to OFF.
2. Disconnect the TCM connector.
3. Measure the resistance of harness between TCM connector and chassis ground.
  Connector & terminal
  
  (T10) No. 1 - Chassis ground:
  
  (T10) No. 6 - Chassis ground:
Is the resistance 1 MΩ or more?

Yes : Go to 3.

No : Go to 2.
CHECK HARNESS INSIDE TRANSMISSION .
CAUTION: Start work after ATF cools down.
1. Remove the transmission valve cover.
2. Check for the harness pinch, damage.
Is there any fault in the harness?

Yes : Replace the transmission harness.

No : Go to 3.
CHECK ATF TEMPERATURE SENSOR .
Measure the resistance between TCM connectors.

Connector & terminal

(T10) No. 1 - (T10) No. 6:

NOTE: Perform the measurements using multiple oil temperatures.

Is resistance as follows?

Fluid temperature 0°C → Approx. 6.0 kΩ

Fluid temperature 20°C → Approx. 2.5 kΩ

Fluid temperature 80°C → Approx. 330 Ω

Yes : Replace the TCM. Ref. to CONTINUOUSLY VARIABLE TRANSMISSION (TR580 IMPREZA)>TRANSMISSION CONTROL MODULE (TCM) .

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