Toyota Sequoia (2005). Manual - part 202

–

DIAGNOSTICS

AUTOMATIC TRANSMISSION

DI–603

797

DTC

P0748

Pressure Control Solenoid ”A” Electrical
(Shift Solenoid Valve SL1)

CIRCUIT 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 either of the
shift solenoid valves, the ECM controls the remaining normal shift solenoid valves to allow the vehicle to be
operated smoothly (See page 

DI–567

).

DTC No.

DTC Detection Condition

Trouble Area

P0748

ECM checks for an open or short circuit in shift solenoid valves

SL1 (1–trip detection logic)

(a) When solenoid, duty ratio equal to 100%

(b) When solenoid is not energized, duty ratio is less than 3%

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 gearshift
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 and illuminates the MIL and stores the DTC. And the ECM per-
forms 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 

DI–567

).

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

It

Specification

Item

Minimum

Maximum

The monitor will run whenever this DTC is

not present.

See page 

DI–545

Battery voltage

10 V or more

–

CPU commanded duty

–

Less than 75%

Ignition switch

ON

Switch

OFF

TYPICAL MALFUNCTION THRESHOLDS

Detection criteria

Threshold

Output signal duty

100%

DIDJB–01

D14168

Electronically Controlled 
Transmission Solenoid

E7

ECM

L

R–B

19

18

SL1+

SL1–

12

4

L

R

E1

SL1+

SL1–

+B

CPU

E7

DI–604

–

DIAGNOSTICS

AUTOMATIC TRANSMISSION

798

COMPONENT OPERATING RANGE

Parameter

Standard value

Output signal duty

Less than 100%

WIRING DIAGRAM

ECM command gearshift

Shift solenoid valve SL1

1st

2nd

3rd

4th

5th

OFF

OFF

OFF

ON

OFF

1

15

2

3

4

5

6

7

8

9

10

11

12

13

14

D11994

SL1

–

SL1

+

E1

Transmission Wire Side:
(Connector Front View):

–

DIAGNOSTICS

AUTOMATIC TRANSMISSION

DI–605

799

INSPECTION PROCEDURE

HINT:

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

1

Inspect transmission wire.

PREPARATION:
Disconnect the transmission wire connector.
CHECK:
Measure the resistance according to the value(s) in the table
below.
OK:

Tester Connection

Specified Condition

20



C (68



F)

12 (SL1+) – 4 (SL1–)

5.0 to 5.6 

Ω

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

Tester Connection

Specified Condition

12 (SL1+) – Body ground

10 k

Ω

 or higher

4 (SL1–) – Body ground

↑

NG

Go to step 3.

OK

D14166

ECM:

SL1+

SL1–

E8

E7

E6

E5

E4

DI–606

–

DIAGNOSTICS

AUTOMATIC TRANSMISSION

800

2

Check harness and connector (Transmission wire – ECM)

PREPARATION:
(a)

Connect the transmission wire connector.

(b)

Disconnect the ECM connector.

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

Tester Connection

Specified Condition

20



C (68



F)

E7 – 19 (SL1+) – E7 – 18 (SL1–)

5.0 to 5.6 

Ω

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

Tester Connection

Specified Condition

E7 – 19 (SL1+) – Body ground

10 k

Ω

 or higher

E7 – 18 (SL1–) – Body ground

↑

NG

Repair or replace the harness or connector
(See page 

IN–35

).

OK

Replace the ECM (See page 

SF–80

).