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

WARNING: This page is about a different car, the 2006 Lexus IS 350. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Wiring Diagram - Pressure Control Solenoid "A" Electrical (Shift Solenoid Valve Sl1)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

HINT:

The shift solenoid valve SL1 is turned on/off normally when the shift lever is in the D position:

POSITION CHART

ECM command gearshift	1st	2nd	3rd	4th	5th	6th
Shift solenoid valve SL1	OFF	OFF	OFF	OFF	ON	ON

INSPECT TRANSMISSION WIRE (SL1)

Disconnect the transmission wire connector from the transmission.

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

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition 20°C (68°F)
11 (SL1+) - 3 (SL1-)	5.0 to 5.6 Ω

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

Standard resistance (Check for short)

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
11 (SL1+) - Body ground	10 kΩ or higher
3 (SL1-) - Body ground

Fig 2: Inspecting Transmission Wire (SL1)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

NG : Go to step 3

OK : GO TO NEXT STEP

CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)

Connect the transmission connector to the transmission.
Disconnect the connector from the ECM.

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

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition 20°C (68°F)
E4-25 (SL1+) - E4-24 (SL1-)	5.0 to 5.6 Ω

Fig 3: Disconnecting E4 Connector From ECM

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Standard resistance (Check for short)

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
E4-25 (SL1+) - Body ground	10 kΩ or higher
E4-24 (SL1-) - Body ground

NG : REPAIR OR REPLACE HARNESS OR CONNECTOR

OK : REPLACE ECM

INSPECT SHIFT SOLENOID VALVE SL1

Remove the shift solenoid valve SL1.

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

Standard resistance

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition 20°C (68°F)
1 - 2	5.0 to 5.6 Ω

Connect the positive (+) lead with a 21 W bulb to terminal 2 and the negative (-) lead to terminal 1 of the solenoid valve connector, then check the movement of the valve.

Fig 4: Checking Continuity Between Solenoid Valve Connector Terminals
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: The solenoid makes an operating sound.

NG : REPLACE SHIFT SOLENOID VALVE SL1

OK : REPAIR OR REPLACE TRANSMISSION WIRE