P0748

A750E AUTOMATIC TRANSMISSION: AUTOMATIC TRANSMISSION SYSTEM (for 1GR-FE): P0748: Pressure Control Solenoid "A" Electrical (Shift Solenoid Valve SL1)

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

DESCRIPTION

Shifting from 1st to 5th is performed in combination with "ON" and "OFF" operation of the shift solenoid valves SL1, SL2, S1, S2 and SR which are controlled by the ECM. If an open or short circuit occurs in any of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be operated smoothly Fail-Safe Chart.





MONITOR DESCRIPTION

This DTC indicates an open or short in the shift solenoid valve SL1 circuit. The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF". When there is an open or short circuit in any shift solenoid valve circuit, the ECM detects the problem, illuminates the MIL and stores the DTC. Then the ECM performs the fail-safe function and turns the other normal shift solenoid valves "ON/OFF". (In case of an open or short circuit, the ECM stops sending current to the circuit.)
While driving and shifting between 4th and 5th gears, if the ECM detects an open or short in the shift solenoid valve SL1 circuit, the ECM determines there is a malfunction Fail-Safe Chart.

MONITOR STRATEGY





TYPICAL ENABLING CONDITIONS

All





Condition (A)





Condition (B)





TYPICAL MALFUNCTION THRESHOLDS





COMPONENT OPERATING RANGE





WIRING DIAGRAM





INSPECTION PROCEDURE

HINT: The shift solenoid valve SL1 is turned ON/OFF normally when the shift lever is in the D position:





PROCEDURE

1. INSPECT TRANSMISSION WIRE (SL1)




(a) Disconnect the transmission wire connector from the transmission.
(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





(c) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for short):





NG -- INSPECT SHIFT SOLENOID VALVE SL1
OK -- Continue to next step.

2. CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)




(a) Connect the transmission wire connector to the transmission.
(b) Disconnect the ECM connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:





(d) Measure the resistance according to the value(s) in the table below.
Standard resistance (Check for short):





NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE ECM
3. INSPECT SHIFT SOLENOID VALVE SL1
(a) Remove the shift solenoid valve SL1.




(b) Measure the resistance according to the value(s) in the table below.
Standard resistance:





(c) Connect the battery's positive (+) lead with a 21 W bulb to terminal 2 and the negative (-) lead to terminal 1 of the solenoid valve connector. Then check that the valve moves and makes an operating noise.
OK:
Valve moves and makes an operating noise.

NG -- REPLACE SHIFT SOLENOID VALVE SL1
OK -- REPAIR OR REPLACE TRANSMISSION WIRE