DTC P0748 Pressure Control Solenoid "A" Electrical (Shift Solenoid Valve SL1): Description

WARNING: This page is about a different car, the 2007 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.

Shifting from 1st to 5th is performed in combination with the ON and OFF operation of the shift solenoid valves SL1, SL2, S1, S2 and SR, which is controlled by the ECM. If an open or short circuit occurs in the shift solenoid valves, the ECM controls the remaining normal shift solenoid valve to allow the vehicle to be operated safely (see FAIL-SAFE CHART ).

DTC DETECTION CONDITION AND TROUBLE AREA

DTC No.	DTC Detection Condition	Trouble Area
P0748	ECM checks for an open or short in shift solenoid valve SL1 circuit while driving and shifting between 4th and 5th gear (1 trip detection logic) Output signal duty equal to 100% HINT: SL1 output signal duty is less than 100% under normal condition	Open or short in shift solenoid valve SL1 circuit Shift solenoid valve SL1 ECM

Reference: Inspect using an oscilloscope.

Check the waveform of the ECM connector.

Standard voltage: Refer to illustration.

WAVEFORM REFERENCE

Item	Content
Tester Connection	E6-19(SL1+) - E6-18(SL1-)
Tool Setting	5 V/DIV., 1 msec./DIV.
Condition	Engine idle speed

Fig 1: Signal Waveform Graph