DTC P0720 Output Speed Sensor Circuit: Wiring Diagram

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

AT Control System. Refer to appropriate SYSTEM WIRING DIAGRAM article.

Fig 1: AT Control System - Wiring Diagram (Output Speed Sensor)

Courtesy of SUBARU OF AMERICA, INC.

DIAGNOSTIC PROCEDURE

Step	Check	Yes	No
1 CHECK TCM I/O SIGNAL. Check the power supply and ground I/O signals. Refer to ELECTRICAL SPECIFICATION .	Is TCM I/O signal OK?	Go to step 2 .	Repair the open or short circuit for power supply and ground.
2 CHECK TCM AND TRANSMISSION HARNESS CONNECTOR. Disconnect the connectors from TCM and transmission. Measure the resistance of harness between TCM connector and transmission connector. Connector & terminal (B55) No. 16 - (B11) No. 2: (B55) No. 24 - (B11) No. 1: (B55) No. 27 - (B11) No. 7:	Is the resistance less than 1 Ω?	Go to step 3 .	Repair the open circuit of harness between TCM and transmission connector.
3 CHECK TCM AND TRANSMISSION HARNESS CONNECTOR. Measure the resistance of harness between TCM connector and chassis ground. Connector & terminal (B55) No. 24 - Chassis ground:	Is the resistance 1 MΩ or more?	Go to step 4 .	Repair the short circuit of harness between TCM and transmission connector.
4 CHECK TCM POWER SUPPLY OUTPUT. Connect the connector to TCM. (Transmission connector is disconnected) Turn the ignition switch to ON. Measure the voltage between transmission connector and chassis ground. Connector & terminal (B11) No. 7 (+) - Chassis ground (-):	Is the voltage 10 - 13 V?	Go to step 5 .	Replace the TCM. Refer to TRANSMISSION CONTROL MODULE (TCM) .
5 CHECK INPUT CIRCUIT OF TCM TURBINE SPEED SENSOR. Measure the voltage variation between TCM connector terminals. Connector & terminal (B11) No. 1 (+) - (B11) No. 2 (-):	Is the voltage 4 - 6 V?	Go to step 6 .	Replace the TCM. Refer to TRANSMISSION CONTROL MODULE (TCM) .
6 CHECK INPUT SIGNAL FOR TCM. Connect all connectors. Lift up the vehicle. Start the engine. Read the data of «Front Wheel Speed» using Subaru Select Monitor. Refer to READ CURRENT DATA . 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. Refer to CLEAR MEMORY MODE .	Does the speedometer indication increase as the «Front Wheel Speed» data increases?	Check the harness of the front vehicle speed sensor circuit, and repair the defective part.	Go to step 7 .
7 CHECK HARNESS CONNECTOR BETWEEN TRANSMISSION AND CONTROL VALVE BODY. Turn the ignition switch to OFF. Disconnect the connector from transmission. Remove the transmission connector from bracket. Lift up the vehicle. Drain the ATF. CAUTION: Do not drain ATF until it cools down. Remove the oil pan. Disconnect the control valve body connector. Measure the resistance between transmission connector and control valve body connector. Connector & terminal (T4) No. 1 - (T10) No. 2:	Is the resistance less than 1 Ω?	Go to step 8 .	Repair the open circuit of harness between control valve body connector and transmission connector.
8 CHECK HARNESS CONNECTOR BETWEEN TRANSMISSION AND CONTROL VALVE BODY. Measure the resistance between transmission ground and control valve body connector. Connector & terminal (T10) No. 2 - Transmission ground:	Is the resistance 1 MΩ or more?	Go to step 9 .	Repair the short circuit of harness between control valve body connector and transmission ground.
9 CHECK HARNESS CONNECTOR BETWEEN CONTROL VALVE BODY AND FRONT VEHICLE SPEED SENSOR. Disconnect the connector from the front vehicle speed sensor. Measure the resistance of the harness between the control valve body connector and front vehicle speed sensor connector. Connector & terminal (T10) No. 2 - (T15) No. 2: (T14) No. 1 - (T15) No. 3: (T14) No. 4 - (T15) No. 1:	Is the resistance less than 1 Ω?	Go to step 10 .	Replace the control valve body. Refer to CONTROL VALVE BODY .
10 CHECK HARNESS CONNECTOR BETWEEN CONTROL VALVE BODY AND FRONT VEHICLE SPEED SENSOR. Measure the resistance of harness between control valve body connector and transmission ground. Connector & terminal (T10) No. 2 - Transmission ground:	Is the resistance 1 MΩ or more?	Replace the front vehicle speed sensor. Refer to FRONT VEHICLE SPEED SENSOR .	Replace the control valve body. Refer to CONTROL VALVE BODY .