LEXUS LS430 2003 Factory Repair Manual

Fig. 194: Transmission Control Switch Reference Chart
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NG: REPLACE TRANSMISSION CONTROL SWITCH (See COMPONENTS
)
OK: Go to next step
4.CHECK HARNESS AND CONNECTOR (TRANSMISSION CONTROL SWITCH - ECM)
a. Connect the transmission control switch connector of shift lock control unit assy.
b. Turn the ignition switch to the ON position, and measure the voltage according to the value(s) in
the table below when the shift lever is moved to each position.

Fig. 195: Identifying ECM Connector Terminals
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Standard:
Fig. 196: Transmission Control Switch Reference Chart

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c. Turn the ignition switch to the LOCK position.
d. Disconnect the ECM connector.

e. Measure the resistance according to the value(s) in the table below when the shift lever is moved to
each position.
Fig. 197: Disconnecting ECM Connector

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Standard:

Fig. 198: Transmission Control Switch Reference Chart
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NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (See ELECTRONIC CIRCUIT
INSPECTION PROCEDURE )
OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS
TABLE
PATTERN SELECT SWITCH CIRCUIT (PWR)
CIRCUIT DESCRIPTION
Passenger side J/B ECU receives pattern select switch information, and sends it through the multiplex
communication system and CAN system to the ECM.
The ECM memory contains the shift programs for the NORMAL, POWER and SNOW patterns, 2 position, L
position and the loc
k-up patterns. By following the programs corresponding to the signals from the pattern
select switch, the neutral start and other various sensors, the ECM switches the solenoid valves ON and OFF,
and controls the transmission gear change and the lock-up clutch operation.
WIRING DIAGRAM

Fig. 199: Pattern Select Switch Circuit (PWR) - Wiring Diagram
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INSPECTION PROCEDURE
1.CHECK HARNESS AND CONNECTOR (PATTERN SELECT SWITCH ASSY NO. 1 - BODY
GROUND)
a. Disconnect the connector of pattern select switch.
b. Measure the resistance according to the value(s) in the table below.

Fig. 200: Identifying Pattern Select Switch Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Standard:
PATTERN SELECT SWITCH NO. 1 - BODY GROUND - RESISTANCE TABLE
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (See ELECTRONIC CIRCUIT
INSPECTION PROCEDURE )
OK: Go to next step
Tester ConnectionSpecified Condition
1 - Body groundBelow 1 ohms

2.INSPECT PATTERN SELECT SWITCH ASSY NO. 1
a. Measure the resistance according to the value(s) in the table below.
Fig. 201: Identifying Pattern Select Switch Terminals

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Standard:

Fig. 202: Pattern Select Switch Reference Chart
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NG: REPLACE PATTERN SELECT SWITCH ASSY NO. 1
OK: Go to next step
3.CHECK HARNESS AND CONNECTOR (PATTERN SELECT SWITCH ASSY NO. 1 -
MULTIPLEX NETWORK BODY ECU)
a. Connect the connector of pattern select switch.
b. Disconnect the passenger side junction block assy (multiplex network body ECU) connector.
c. Measure the resistance between terminal PWR of passenger side junction block assy (multiplex
network body ECU) and body ground.
Standard:
Fig. 203: Pattern Select Switch Reference Chart

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Fig. 204: Identifying Passenger Side Junction Block Assy
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NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (See ELECTRONIC CIRCUIT
INSPECTION PROCEDURE )
OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS
TABLE
PATTERN SELECT SWITCH CIRCUIT (SNOW)
CIRCUIT DESCRIPTION
Passenger side J/B ECU receives pattern select switch information, and sends it through the multiplex
communication system and CAN system to the ECM.
ECT SNOW is the system that operates the throttle motor to control engine output to reduce skidding of the
driving wheels, guarantee takeoff acceleration, driving straightness and turning stability.
WIRING DIAGRAM

Fig. 205: Pattern Select Switch Circuit (SNOW) - Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.DRIVING TEST
a. Start the engine.
b. Turn the ECT SNOW switch "OFF" (Normal drive mode).
c. Confirm vehicle response by driving from a parked position to fully depressing the accelerator
pedal.
d. Turn the ECT SNOW switch "ON" and perform the same check as (c).
Confirm that there is a difference between ECT SNOW switch "ON" and "OFF".
Driving test should be done on a paved road (a nonskid road).
Make sure not to use the TRAC system when testing a vehicle equipped with one.
OK:
There is a difference in acceleration between "ON" and "OFF".
NG: Go to step 2
OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS
TABLE
2.CHECK HARNESS AND CONNECTOR (PATTERN SELECT SWITCH ASSY NO. 1 - BODY
GROUND)