AUTOMATIC TRANSMISSION (DIAGNOSTICS)(4AT) > Diagnostic Procedure with Diagnostic Trouble Code (DTC) > DTC P0748 PRESSURE CONTROL SOLENOID “A” ELECTRICAL

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

DTC P0748 PRESSURE CONTROL SOLENOID “A” ELECTRICAL

DTC DETECTING CONDITION:

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

TROUBLE SYMPTOM:

Excessive shift shock

WIRING DIAGRAM:

STEP	CHECK	YES	NO
1.CHECK HARNESS CONNECTOR BETWEEN TCM AND TRANSMISSION. 1) Turn the ignition switch to OFF. 2) Disconnect the connector from transmission and TCM. 3) Measure the resistance of the harness between TCM connector and transmission connector. Connector & terminal (B55) No. 3 — (B11) No. 2: (B55) No. 4 — (B11) No. 1:	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 CHASSIS GROUND. Measure the resistance of the harness between TCM connector and chassis ground. Connector & terminal (B55) No. 3 — Chassis ground: (B55) No. 4 — Chassis ground:	Is the resistance 1 MΩ or more?		Repair the short circuit of 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?	Replace the TCM.
4.CHECK LINE PRESSURE LINEAR 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, and disconnect the connector from control valve body. 4) Measure the resistance of line pressure linear solenoid connector terminals. Connector & terminal (AT2) No. 5 — No. 10:	Is the resistance 4 — 8 Ω?		Replace the 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. 10: (T4) No. 1 — (AT2) No. 5:	Is the resistance less than 1 Ω?		Repair the open circuit of 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 1 MΩ or more?	Check for poor contact in the line pressure linear solenoid and transmission harness or connectors, and repair the fault location.	Repair the short circuit of harness between line pressure linear solenoid and transmission connector.