Toyota Tacoma 2015-2018 Service Manual: Pressure Control Solenoid "A" Electrical (Shift Solenoid Valve SL1) (P0748)

Toyota Tacoma 2015-2018 Service Manual / Ac60e Automatic Transmission / Transaxle / Automatic Transmission System(for 2tr-fe) / Pressure Control Solenoid "A" Electrical (Shift Solenoid Valve SL1) (P0748)

DESCRIPTION

Changing from 1st to 6th is performed by the ECM turning shift solenoid valves SL1, SL2, SL3 and SL4 on and off. 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 (See page ).

DTC No.	DTC Detection Condition	Trouble Area
P0748	An open or short circuit (output signal duty is 0% or 100%) is detected by the ECM in the shift solenoid valve SL1 circuit while driving and shifting gears (SL1 output signal duty is more than 3% and less than 100% under normal conditions) (1 trip detection logic).	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 or off. When there is an open or short circuit in any of the shift solenoid valve circuits, the ECM detects the problem and illuminates the MIL and stores the DTC. The ECM also performs the fail-safe function and turns the other normal shift solenoid valves on or off. (In case of an open or short circuit, the ECM stops sending current to the circuit.)

While driving and shifting 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 ).

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	Immediately
Sequence of operation	None

TYPICAL ENABLING CONDITIONS

All:

The monitor will run whenever the following DTCs are not stored	None
Solenoid current cut status	Not cut
Ignition switch	ON
Starter	OFF

Condition (A):

Battery voltage

12 V or higher

Condition (B):

Battery voltage	10 V or higher, and below 12 V
Target current	Below 0.75 A

Condition (C):

Battery voltage	8 V or higher
Target current	0.25 A or higher

TYPICAL MALFUNCTION THRESHOLDS

One of the following conditions is met: Condition (A), (B) or (C)

Condition (A) and (B):

Output duty cycle

100% or more

Condition (C):

Output duty cycle

0% or less

COMPONENT OPERATING RANGE

Output duty cycle

More than 3%, and less than 100%

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Perform the universal trip to clear permanent DTCs (See page ).
Perform registration and/or initialization when parts related to the automatic transmission are replaced (See page ).

HINT:

The following table shows normal operation of the shift solenoid valve SL1 when the shift lever is in D:

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

After the repair, clear the DTCs and perform the following procedure to check that DTCs are not output.
1. Perform the D Position Shift Test in Road Test (See page ).
2. Check for DTCs again (See page ).

PROCEDURE

1.	INSPECT TRANSMISSION WIRE (SHIFT SOLENOID VALVE SL1)

(a) Disconnect the E1 transmission wire connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
25 (SL1+) - 26 (SL1-)	20°C (68°F)	5.0 to 5.6 Ω
25 (SL1+) - Body ground	Always	10 kΩ or higher
26 (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 ECM connector.

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

Standard Resistance:

Tester Connection	Condition	Specified Condition
E19-9 (SL1+) - E19-8 (SL1-)	20°C (68°F)	5.0 to 5.6 Ω
E19-9 (SL1+) - Body ground	Always	10 kΩ or higher
E19-8 (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

(a) Remove shift solenoid valve SL1 (See page ).

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

Standard Resistance:

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

OK:

Measurement Condition	Specified Condition
Battery positive (+) with a 21 W bulb → Terminal 1 Battery negative (-) → Terminal 2	Valve moves and makes an operating noise

Text in Illustration

*1	Shift Solenoid Valve SL1

REPLACE TRANSMISSION WIRE

REPLACE SHIFT SOLENOID VALVE SL1

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