Toyota 4Runner: Pressure Control Solenoid "A" Electrical (Shift Solenoid Valve SL1) (P0748)

Toyota 4Runner Service Manual / Drivetrain / A750e Automatic Transmission / Transaxle / Automatic Transmission System / Pressure Control Solenoid "A" Electrical (Shift Solenoid Valve SL1) (P0748)

DESCRIPTION

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 are controlled by the ECM. If an open or short circuit occurs in one of the shift solenoid valves, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be operated smoothly (See page ).

DTC Code	DTC Detection Condition	Trouble Area
P0748	The ECM checks for an open or short in the shift solenoid valve SL1 circuit while driving and shifting between 4th and 5th gear (1-trip detection logic). Output signal duty equals 100%. HINT: SL1 output signal duty is less than 100% under normal conditions.	Open or short in shift solenoid valve SL1 circuit Shift solenoid valve SL1 ECM

DTC Code

DTC Detection Condition

Trouble Area

P0748

The ECM checks for an open or short in the shift solenoid valve SL1 circuit while driving and shifting between 4th and 5th gear (1-trip detection logic).

Output signal duty equals 100%.

HINT:

SL1 output signal duty is less than 100% under normal conditions.

Open or short in shift solenoid valve SL1 circuit
Shift solenoid valve SL1
ECM

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 (See page ).

MONITOR STRATEGY

Related DTCs	P0748: Shift solenoid valve SL1/Range check
Required sensors/Components	Shift solenoid valve SL1
Frequency of operation	Continuous
Duration	1 sec.
MIL operation	Immediate
Sequence of operation	None

TYPICAL ENABLING CONDITIONS

All

The monitor will run whenever the following DTCs are not stored	None
Battery voltage	8 V or higher
Ignition switch	ON
Starter	OFF

Condition (A)

Solenoid current cut status	Not cut
Battery voltage	11 V or higher
Target duty cycle	19% or more

Condition (B)

Target duty cycle

100%

TYPICAL MALFUNCTION THRESHOLDS

Solenoid status from solenoid driver MIC

Failure

COMPONENT OPERATING RANGE

Output signal duty

Less than 100%

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Perform the universal trip to clear permanent DTCs (See page ).

HINT:

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

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

PROCEDURE

1.	INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE SL1)

(a) Disconnect the B32 transmission wire connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
12 (SL1+) - 4 (SL1-)	20°C (68°F)	5.0 to 5.6 Ω
12 (SL1+) - Body ground	Always	10 kΩ or higher
4 (SL1-) - Body ground	Always	10 kΩ or higher

Text in Illustration

*a	Component without harness connected (Transmission Wire)

GO TO STEP 3

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

(a) Disconnect the B38 ECM connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
B38-33 (SL1+) - B38-32 (SL1-)	20°C (68°F)	5.0 to 5.6 Ω
B38-33 (SL1+) - Body ground	Always	10 kΩ or higher
B38-32 (SL1-) - Body ground	Always	10 kΩ or higher

Text in Illustration

*a	Rear view of wire harness connector (to ECM)

REPLACE ECM

REPAIR OR REPLACE HARNESS OR CONNECTOR

3.	INSPECT SHIFT SOLENOID VALVE SL1

REPAIR OR REPLACE TRANSMISSION WIRE

REPLACE SHIFT SOLENOID VALVE SL1

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