DTC P0748 Pressure Control Solenoid "A" Electrical

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

DTC DETECTING CONDITION:

Output signal circuit of line pressure linear solenoid is open or shorted.

TROUBLE SYMPTOM:

Excessive shift shock

WIRING DIAGRAM:

Fig 1: Wiring Diagram - Pressure Control Solenoid "A" Electrical

Courtesy of SUBARU OF AMERICA, INC.

DTC P0748 DIAGNOSTIC PROCEDURE

Step	CHECK	Yes	No
1 CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION. Turn the ignition switch to OFF. Disconnect the connector from transmission and TCM. Measure the resistance of harness between TCM and transmission connector. Connector & terminal (B55) No. 19 - (B11) No. 2: (B55) No. 20 - (B11) No. 1:	Is the resistance less than 1 Ω?	Go to step 2 .	Repair the open circuit in harness between TCM and transmission connector.
2 CHECK HARNESS CONNECTOR BETWEEN TCM AND CHASSIS GROUND. Measure the resistance of harness between TCM connector and chassis ground. Connector & terminal (B55) No. 19 - Chassis ground: (B55) No. 20 - Chassis ground:	Is the resistance more than 1 MΩ?	Go to step 3 .	Repair the short circuit in harness between TCM and transmission connector.
3 CHECK LINE PRESSURE LINEAR SOLENOID. Measure the resistance between transmission connector receptacle's terminals. Connector & terminal (T4) No. 1 - No. 2:	Is the resistance 4 - 8 Ω?	Go to step 5 .	Go to step 4 .
4 CHECK LINE PRESSURE LINEAR SOLENOID (IN TRANSMISSION). Remove the transmission connector from bracket. Drain the ATF. CAUTION: Do not drain the ATF until it cools down. Remove the oil pan, and disconnect the connector from control valve body. Measure the resistance between line pressure linear solenoid connector terminals. Connector & terminal (AT2) No. 2 - No. 4:	Is the resistance 4 - 8 Ω?	Go to step 5 .	Replace the control valve body. < Ref. to CONTROL VALVE BODY . >
5 CHECK HARNESS CONNECTOR BETWEEN TRANSMISSION AND LINE PRESSURE LINEAR SOLENOID. Measure the resistance of harness between line pressure linear solenoid and transmission connector. Connector & terminal (T4) No. 2 - (AT2) No. 4: (T4) No. 1 - (AT2) No. 2:	Is the resistance less than 1 Ω?	Go to step 6 .	Repair the open circuit in harness between line pressure linear solenoid and transmission connector.
6 CHECK HARNESS CONNECTOR BETWEEN TRANSMISSION AND LINE PRESSURE LINEAR SOLENOID. Measure the resistance of harness between transmission connector and transmission ground. Connector & terminal (T4) No. 1 - Transmission ground: (T4) No. 2 - Transmission ground:	Is the resistance more than 1 MΩ?	Even if the SPORT indicator light is blinking, the circuit has returned to normal condition at this time. A temporary poor contact of connector or harness may be the cause. Repair the harness or connector in line pressure linear solenoid and transmission.	Repair the short circuit in harness between line pressure linear solenoid and transmission connector.