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

DTC P0763 SHIFT SOLENOID “C” ELECTRICAL

DTC DETECTING CONDITION:

Output signal circuit of high clutch duty solenoid is open or shorted.

TROUBLE SYMPTOM:

Excessive shift shock

WIRING DIAGRAM:

• FF model

• AWD model

STEPCHECKYESNO

1.CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION.

1) Turn the ignition switch to OFF.

2) Disconnect the connectors from TCM and transmission.

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

Connector & terminal

(B54) No. 6 — (B11) No. 7:

Is the resistance less than 1 Ω?

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

2.CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION.

Measure the resistance of the harness connector between TCM connector and chassis ground.

Connector & terminal

(B54) No. 6 — Chassis ground:

Is the resistance 1 MΩ or more?

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

3.CHECK HIGH CLUTCH DUTY SOLENOID.

Measure the resistance between transmission connector receptacle’s terminals.

Connector & terminal

(T4) No. 7 — No. 20:

Is the resistance between 2.0 — 6.0 Ω?

4.CHECK OUTPUT SIGNAL FROM TCM USING SUBARU SELECT MONITOR.

1) Connect the connectors to TCM and transmission.

2) Lift up the vehicle.

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

4) Start the engine.

5) Run the Subaru Select Monitor.

6) Warm up the engine until the ATF temperature exceeds 80°C (176°F).

7) Read the data of “High Clutch Duty Ratio” using Subaru Select Monitor.

8) Shift the select lever to “D”, and slowly increase vehicle speed to measure at 3rd or 4th.

NOTE:

The speed difference between front and rear wheels lights the ABS warning light, but this does not indicate a malfunction. If the warning light is illuminated, clear the memory of ABS or VDC after completing AT control diagnosis.

Is the measured value 0%?

5.CHECK OUTPUT SIGNAL OF TCM.

Return the engine to idling speed and shift the select lever to “N” range.

NOTE:

The speed difference between front and rear wheels lights the ABS warning light or the VDC warning light, but this does not indicate a malfunction. If the warning light is illuminated, clear the memory of ABS or VDC after completing AT control diagnosis.

Is the measured value 100%?

Check the harnesses or connectors between TCM and transmission, and repair the defective part.

6.CHECK POOR CONTACT.

Is there poor contact of high clutch duty solenoid circuit?

Repair the poor contact.

Replace the TCM.

7.CHECK HIGH CLUTCH DUTY SOLENOID (IN TRANSMISSION).

1) Remove the transmission connector from bracket.

2) Drain the automatic transmission fluid.

CAUTION:

Do not drain ATF until it cools down.

3) Remove the oil pan.

4) Disconnect the connector from the control valve body.

5) Measure the resistance between high clutch duty solenoid connector and transmission ground.

Connector & terminal

FF model

(AT3) No. 3 — Transmission ground:

AWD model

(AT2) No. 3 — Transmission ground:

Is the resistance between 2.0 — 6.0 Ω?

Replace the control valve body.

8.CHECK HARNESS CONNECTOR BETWEEN HIGH CLUTCH DUTY SOLENOID AND TRANSMISSION.

Measure the resistance of harness between high clutch duty solenoid and transmission connector.

Connector & terminal

FF model

(T4) No. 7 — (AT3) No. 3:

AWD model

(T4) No. 7 — (AT2) No. 3:

Is the resistance less than 1 Ω?

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

9.CHECK HARNESS CONNECTOR BETWEEN HIGH CLUTCH DUTY SOLENOID AND TRANSMISSION.

Measure the resistance of harness between transmission connector and transmission ground.

Connector & terminal

(T4) No. 7 — Transmission ground:

Is the resistance 1 MΩ or more?

Check the harnesses or connectors between high clutch duty solenoid and transmission, and repair the defective part.

Repair the short circuit of harness between high clutch duty solenoid and transmission connector.