AUTOMATIC TRANSMISSION (DIAGNOSTICS)(4AT) > Diagnostic Procedure with Diagnostic Trouble Code (DTC)

DTC P0712 TRANSMISSION FLUID TEMPERATURE SENSOR CIRCUIT LOW INPUT

DTC DETECTING CONDITION:

Input signal circuit to ATF temperature sensor is open or shorted.

TROUBLE SYMPTOM:

Excessive shift shock

WIRING DIAGRAM:

• FF model

• AWD model

STEPCHECKYESNO

1.CHECK HARNESS CONNECTOR BETWEEN TCM AND ATF TEMPERATURE SENSOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from transmission and TCM.

3) Measure the resistance of harness between TCM and transmission connector.

Connector & terminal

(B55) No. 12 — (B11) No. 15:

(B55) No. 23 — (B11) No. 11:

Is the resistance less than 1 Ω?

Repair the open circuit of harness between TCM and transmission connector.

2.CHECK ATF TEMPERATURE SENSOR.

1) Turn the ignition switch to OFF.

2) Connect the connectors to transmission and TCM.

3) Start the engine.

4) Warm up the transmission until the ATF temperature exceeds 80°C (176°F).

5) Disconnect the connector from transmission.

6) Measure the resistance between transmission connector terminals.

Connector & terminal

(T4) No. 11 — No. 15:

Is the resistance between 300 — 800 Ω?

3.CHECK ATF TEMPERATURE SENSOR.

Measure the resistance between transmission connector terminals.

Connector & terminal

(T4) No. 11 — No. 15:

Does the resistance value increase while the ATF temperature decreases?

4.CHECK INPUT SIGNAL FOR TCM.

1) Connect the connector to transmission.

2) Connect the Subaru Select Monitor to data link connector.

3) Turn the ignition switch to ON.

4) Read the data of “ATF Temp.” using the Subaru Select Monitor.

Does the ATF temperature gradually decrease?

Check the harnesses or connectors between ATF temperature sensor and transmission, and repair the defective part.

5.CHECK HARNESS CONNECTOR BETWEEN TRANSMISSION AND ATF TEMPERATURE SENSOR.

1) Turn the ignition switch to OFF.

2) Disconnect the connector from transmission.

3) Remove the transmission connector from bracket.

4) Lift up the vehicle.

5) Drain the automatic transmission fluid.

CAUTION:

Do not drain ATF until it cools down.

6) Remove the oil pan.

7) Disconnect the connector from the control valve.

8) Measure the resistance of harness between ATF temperature sensor and transmission connector.

Connector & terminal

FF model

(T4) No. 11 — (AT2) No. 1:
(T4) No. 15 — (AT2) No. 3:

AWD model

(T4) No. 11 — (AT2) No. 4:
(T4) No. 15 — (AT2) No. 9:

Is the resistance less than 1 Ω?

Replace the control valve body.

Repair the open circuit of harness between ATF temperature sensor and transmission connector.

6.CHECK POOR CONTACT.

Is there poor contact of ATF temperature sensor circuit?

Repair the poor contact.

Replace the TCM.