2003 LEXUS LS430 Ecm

The linear solenoid valve (SLT) controls the transmission line pressure for smooth transmission operation based
on signals from the throttle position sensor and the vehicle speed sensor. The ECM adjusts the duty cycle of the
SLT solenoid valve to control hydraulic line pressure coming from the primary regulator valve. Appropriate line
pressure assures smooth shifting with varying engine outputs.
(*): Duty Ratio
The duty ratio is the ratio of the period of continuity in one cycle. For example, if A is the period of continuity
in one cycle, and B is the period of non-continuity, then Duty Ratio=A/(A+B) x 100 (%)
Fig. 158: Identifying Line Pressure Graph

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Fig. 161: DTC Reference Chart
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MONITOR DESCRIPTION
The ECM calculates the amount of heat absorbed by the friction material based on the difference in revolution
(clutch slippage) between the turbine and output shaft. The ECM turns on the MIL and outputs this DTC when
the amount of heat absorption exceeds the specified value.
When the shift solenoid valve SLT remains on, oil pressure goes down and clutch engagement force decreases.
MONITOR STRATEGY
MONITOR STRATEGY TABLE
TYPICAL ENABLING CONDITIONS
ON malfunction
Related DTCsP2714: Shift solenoid valve SLT/ON malfunction
Required sensors/ComponentsShift solenoid valve SLT
Frequency of operationContinuous
DurationBetween starting in the 1st gear and stopping in the
4th gear
MIL operation2 driving cycles
Sequence of operationNone

OK: Go to next step
3.INSPECT TRANSMISSION VALVE BODY ASSY (See chapter 2 in PROBLEM
SYMPTOMS TABLE )
OK:
There are no foreign objects on each valve and they operate smoothly.
NG: REPAIR OR REPLACE TRANSMISSION VALVE BODY ASSY (See step 6 on
REPLACEMENT
)
OK: Go to next step
4.INSPECT TORQUE CONVERTER CLUTCH ASSY (See INSPECTION
)
OK:
The torque converter clutch operates normally.
NG: REPLACE TORQUE CONVERTER CLUTCH ASSY
OK: REPAIR OR REPLACE AUTOMATIC TRANSMISSION ASSY (See
COMPONENTS
)
DTC P2716: PRESSURE CONTROL SOLENOID "D" ELECTRICAL (SHIFT SOLENOID SLT)
CIRCUIT DESCRIPTION
See DTC P2714 PRESSURE CONTROL SOLENOID "D" PERFORMANCE (SHIFT SOLENOID
VALVE SLT) .
Fig. 166: DTC Reference Chart

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MONITOR DESCRIPTION
When an open or short in the linear solenoid valve (SLT) circuit is detected, the ECM interprets this as a fault.
The ECM will turn ON the MIL and store the DTC.
MONITOR STRATEGY

Fig. 169: Identifying Transmission Wire Terminals
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NG: Go to step 3
OK: Go to next step
2.CHECK HARNESS AND CONNECTOR (TRANSMISSION WIRE - ECM)
a. Connect the transmission wire connector to the transmission.
b. Disconnect the ECM connector.
c. Measure the resistance according to the value(s) in the table below.

Fig. 170: Disconnecting ECM Connector
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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 - 35 (SLT+) - E6 - 34 (SLT-)5.0 to 5.6 ohms

Fig. 171: Tester Connection Reference Chart
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NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (See ELECTRONIC CIRCUIT
INSPECTION PROCEDURE )
OK: REPLACE ECM (See REPLACEMENT
)
3.INSPECT SHIFT SOLENOID VALVE (SLT)
a. Remove the shift solenoid valve (SLT).
b. Measure the resistance according to the value(s) in the table below.
Standard:
SHIFT SOLENOID VALVE (SLT) - 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 P2757: TORQUE CONVERTER CLUTCH PRESSURE CONTROL SOLENOID
PERFORMANCE (SHIFT SOLENOID VALVE SLU)
SYSTEM DESCRIPTION
The ECM uses the signals from the throttle position sensor, Air-flow meter, turbine (input) speed sensor, output
speed sensor and crankshaft position sensor to monitor the engagement condition of the lock-up clutch.
Then the ECM compares the engagement condition of the lock-up clutch with the lock-up schedule in the ECM
memory to detect a mechanical problems of the shift solenoid valve SLU, valve body and torque converter
clutch.
Fig. 173: Identifying Manual Transmission

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Fig. 174: Identifying Lock-Up Operation Pressure Graph
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Fig. 175: DTC Reference Chart

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MONITOR DESCRIPTION
Torque converter lock-up is controlled by the ECM based on turbine (input) speed sensor NT, output speed
sensor SP2, engine rpm, engine load, engine temperature, vehicle speed, transmission temperature, and gear
selection. The ECM determines the lock-up status of the torque converter by comparing the engine rpm (NE) to
the input turbine rpm (NT). The ECM calculates the actual transmission gear by comparing input turbine rpm
(NT) to output shaft rpm (SP2). When conditions are appropriate, the ECM requests "lock-up" by applying
control volta
ge to shift solenoid SLU. When the SLU is turned on, solenoid SLU applies pressure to the lock-up