2003 LEXUS LS430 Ecm

TYPICAL MALFUNCTION THRESHOLDS TABLE
COMPONENT OPERATING RANGE
COMPONENT OPERATING RANGE TABLE
WIRING DIAGRAM
Fig. 89: DTC P0748 - Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
HINT:
The shift solenoid valve SL1 is turned on/off normally when the shift lever is in the D position:
GEARSHIFT SPECIFICATION TABLE
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:
Output signal duty100%
Output signal dutyLess than 100%
ECM
command
gearshift
1st2nd3rd4th5th6th
Shift solenoid
valve SL1OFFOFFOFFOFFONON

NG: Go to step 3
OK: Go to next step
2.CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)
a. Connect the transmission connector to the transmission.
b. Disconnect the connector from the ECM.
c. Measure the resistance according to the value(s) in the table below.
Fig. 92: Disconnecting Connector From ECM

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Standard:
TRANSMISSION WIRE - ECM - RESISTANCE TABLE
d. Measure the resistance according to the value(s) in the table below.
Standard (Check for short):
Tester ConnectionSpecified Condition 20°C (68°F)
E6-25 (SL1+) - E6-24(SL1-)5.0 to 5.6 ohms

Fig. 93: Tester Connection Reference Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (See ELECTRONIC CIRCUIT
INSPECTION PROCEDURE )
OK: REPLACE ECM (See REPLACEMENT
)
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:
SHIFT SOLENOID VALVE (SL1) - RESISTANCE TABLE
c. 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.
OK:
The solenoid makes an operating noise.
Tester ConnectionSpecified Condition 20°C (68°F)
1 - 25.0 to 5.6 ohms

OK: REPAIR OR REPLACE TRANSMISSION WIRE (See step 5 on REPLACEMENT)
DTC P0751: SHIFT SOLENOID "A" PERFORMANCE (SHIFT SOLENOID VALVE S1)
SYSTEM DESCRIPTION
The ECM uses signals from the output shaft speed sensor and input speed sensor to detect the actual gear
position (1st, 2nd, 3rd, 4th, 5th or 6th gear).
Then the ECM compares the actual gear with the shift schedule in the ECM memory to detect mechanical
problems of the shift solenoid valves and valve body.
Fig. 95: DTC Reference Chart

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
HINT:
Gear positions in the event of a solenoid valve mechanical problem:
Fig. 96: Gear Position Specification

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Gear position during fail-safe operation:
If an
y malfunction is detected, the ECM changes into the fail-safe mode to shift into the gear positions as

shown in the table below.
Fig. 97: Gear Position Specification

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
MONITOR DESCRIPTION
This DTC indicates "stuck ON malfunction" or "stuck OFF malfunction" of the shift solenoid valve S1.
The ECM commands gear shifts by turning the shift solenoid valves "ON/OFF". When the gear position
commanded by the ECM and the actual gear position are not same, the ECM illuminates the MIL and stores the
DTC.
MONITOR STRATEGY
Fig. 98: Monitor Strategy Reference Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
TYPICAL ENABLING CONDITIONS
The following items are common to all conditions below.
TYPICAL ENABLING CONDITIONS TABLE
The monitor will run whenever this DTC is not
present.
See LIST OF DISABLE A MONITOR

OFF malfunction (A)
TYPICAL ENABLING CONDITIONS TABLE - OFF MALFUNCTION A
OFF malfunction (B)
TYPICAL ENABLING CONDITIONS TABLE - OFF MALFUNCTION B
OFF malfunction (C)
TYPICAL ENABLING CONDITIONS TABLE - OFF MALFUNCTION C
Turbine speed sensor circuitNot circuit malfunction
Output speed sensor circuitNot circuit malfunction
Shift solenoid valve S1 circuitNot circuit malfunction
Shift solenoid valve S2 circuitNot circuit malfunction
Shift solenoid valve S3 circuitNot circuit malfunction
Shift solenoid valve S4 circuitNot circuit malfunction
Shift solenoid valve SR circuitNot circuit malfunction
Shift solenoid valve SL1 circuitNot circuit malfunction
Shift solenoid valve SL2 circuitNot circuit malfunction
ECT (Engine coolant temperature) sensor circuitNot circuit malfunction
KCS sensor circuitNot circuit malfunction
ETCS (Electric throttle control system)Not system down
Transmission range"D"
ECT40°C (104°F) or more
Spark advance from Max. retard timing by KCS
control0° CA or more
EngineStarting
ECM selected gear5th
Vehicle speed2 km/h (1.2 mph) or more
Throttle valve opening angle6.5% or more at 2,000 rpm (Conditions vary with
engine speed)
ECM selected gear2nd
Vehicle speed2 km/h (1.2 mph) or more
Output speed2nd --> 1st down shift point or more
Throttle valve opening angle6.5% or more at 2,000 rpm (Conditions vary with
engine speed)
Current ECM selected gear6th
Last ECM selected gear5th
Vehicle speed (During transition from 5th to 6th
gear)Less than 100 km/h (62.2 mph)

OFF malfunction (D)
TYPICAL ENABLING CONDITIONS TABLE - OFF MALFUNCTION D
ON malfunction (A)
TYPICAL ENABLING CONDITIONS TABLE - ON MALFUNCTION A
ON malfunction (B)
TYPICAL ENABLING CONDITIONS TABLE - ON MALFUNCTION B
TYPICAL MALFUNCTION THRESHOLDS
[OFF malfunction]
Both of the following conditions are met:
OFF malfunction (A)
OFF malfunction (B), (C) or (D)
OFF malfunction (A)
TYPICAL MALFUNCTION THRESHOLDS TABLE - OFF MALFUNCTION A
OFF malfunction (B)
TYPICAL MALFUNCTION THRESHOLDS TABLE - OFF MALFUNCTION B
ECM selected gear6th
Engine speed-Turbine speed (NE-NT) (After
transition from 5th to 6th gear)Less than 150 rpm
Vehicle speedLess than 100 km/h (62.2 mph)
ECM selected gear1st
Vehicle speed2 km/h (1.2 mph) or more and Less than 40 km/h
(24.9 mph)
Engine speed-Turbine speed (NE-NT)50 rpm or more
ECM selected gear5th
Vehicle speed2 km/h (1.2 mph) or more
Throttle valve opening angle6.5% or more at 2,000 rpm (Conditions vary with
engine speed)
Turbine speed/Output speed (NT/NO)0.66 or more and 0.80 or less (This means actual
gear is 5th)
Turbine speed/Output speed (NT/NO)3.08 or more and 7.50 or less (This means actual
gear is 1st)

c. Connect the hand-held tester together with the CAN VIM (controller area network vehicle interface
module) to the DLC3.
d. Turn the ignition switch to the ON position.
e. Push the "ON" button of the hand-held tester.
f. Clear the DTC.
g. Select the item "DIAGNOSIS/ENHANCED OBD II/ACTIVE TEST/SHIFT",
h. According to the display on tester, perform the "ACTIVE TEST".
HINT:
While driving, the shift position can be forcibly changed with the hand-held tester.
Comparing the shift position commanded by the ACTIVE TEST with the actual shift position enables you to
confirm the problem (see FAIL
-SAFE CHART ).
Fig. 99: Test Item Reference Chart

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
HINT:
This test can be conducted when the vehicle speed is 50 km/h (31 mph) or less.
The 4th to 5th and 5th to 6th up-shiftings must be performed with the accelerator pedal released.
The 6th to 5th and 5th to 4th down-shiftings must be performed with the accelerator pedal released.
Do not operate the accelerator pedal for at least 2 seconds after shifting and do not shift successively.
The shift position commanded by the ECM is shown in the DATA LIST/SHIFT display on the hand-held
tester.
<0037004b004800030056004b004c00490057000300560052004f004800510052004c0047000300590044004f005900480003003600140003004c00560003005700580055005100480047000300520051001200520049004900030051005200550050004400
4f004f005c0003005a004b0048005100030057004b00480003[shift lever is in the D position:
GEARSHIFT SPECIFICATION TABLE
ECM
command
gearshift
1st2nd3rd4th5th6th
Shift solenoid
valve S1OFFONONONONON