2003 LEXUS LS430 Identifying ac

Fig. 33: Connecting Hand-Held Tester To DLC3
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1.Constant speed control mode and vehicle-to-vehicle distance control mode:
If the following conditions are detected while the dynamic laser cruise control is in operation, the system
clears the stored vehicle speed in the ECM and cancels the dynamic laser cruise control operation.
Fig. 34: Identifying CRUISE Main Indicator Light And Master Warning Light

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Fig. 35: Fail
-Safe Chart
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2.Only in the vehicle-to-vehicle distance control mode:
If the following conditions are detected while the dynamic laser cruise control is in operation, the system
clears the stored vehicle speed in the ECM and cancels the dynamic laser cruise control operation.
Fig. 36: Identifying CRUISE Main Indicator Light And Master Warning Light

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Fig. 37: Fail
-Safe Chart
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3.Only in the vehicle-to-vehicle distance control mode:
If the following conditions are detected while the dynamic laser cruise control is in operation, the system
maintains the stored vehicle speed in the ECM and cancels the d
ynamic laser cruise control operation.

Fig. 38: Identifying Master Warning Light
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Fig. 39: Fail
-Safe Chart (1 Of 2)
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4.Constant speed control mode and vehicle-to-vehicle distance control mode:
If the following conditions are detected while the dynamic laser cruise control is in operation, the system
clears the stored vehicle speed and cancels the dynamic laser cruise control operation.
HINT:
In the vehicle-to-vehicle distance control mode, the stored vehicle speed in the ECM is maintained.
Fig. 40: Fail
-Safe Chart (2 Of 2)

Fig. 45: Identifying Stop Lamp Switch Assy Connector
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OK: Go To Next Step.
3.CHECK HARNESS AND CONNECTOR (STOP LAMP SWITCH - BATTERY)
a. Measure the voltage according to the value(s) in the table below.
Standard:
STOP LAMP SWITCH TERMINALS VOLTAGE SPECIFICATION
Tester connectionConditionSpecified condition
S19-2 - Body groundAlways10 to 14 V
S19-3 - Body groundIgnition SW ON10 to 14 V

Fig. 46: Identifying Stop Lamp Switch Assy Connector
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NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go To Next Step.
4.INSPECT ECM
a. Reconnect the stop lamp switch connector.
b. Disconnect the E2 and E3 connectors from the ECM.
c. Turn the ignition switch to the ON position.
d. Measure the voltage according to the value(s) in the table below.
Standard:
ECM TERMINALS VOLTAGE SPECIFICATION
Pedal conditionTester connectionSpecification
DepressedE2-4 (STP) - Body ground10 to 14 V
ReleasedE2-4 (STP) - Body groundBelow 1 V

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A: REPLACE ECM (SEE REPLACEMENT
)
5.INSPECT DRIVER SIDE J/B
a. Measure the voltage according to the value(s) in the table below.
Fig. 48: Identifying Driver Side Junction Block ECU Connector Terminals

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Standard:
ECU CONNECTOR VOLTAGE RESISTANCE SPECIFICATION
NG: Go to step 6
Pedal conditionTester connectionSpecification
DepressedD3-12 (STPO) - Body ground10 to 14 V
ReleasedD3-12 (STPO) - Body groundBelow 1 V

OK: REPAIR OR REPLACE HARNESS OR CONNECTOR (DRIVER SIDE J/B ECU -
ECM)
6.INSPECT DRIVER SIDE J/B
a. Measure the voltage according to the value(s) in the table below.
Fig. 49: Identifying Driver Side Junction Block ECU Connector Terminals

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Standard:
ECU CONNECTOR TERMINALS VOLTAGE SPECIFICATION
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (STOP LAMP SWITCH -
DRIVER SIDE J/B ECU)
Pedal conditionTester connectionSpecification
DepressedD3-13 (STPI) - Body ground10 to 14 V
ReleasedD3-13 (STPI) - Body groundBelow 1 V

Fig. 59: Identifying Laser Sensor Terminals
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c. Check the signal waveform between terminal LRDD (L1-3) of the laser sensor and body ground.
OK:
A waveform similar to that in the illustration to the left is output.
HINT:
Gauge set: 1 V/DIV, 2 ms/DIV
Condition: Ignition switch ON
NG: REPLACE LASER SENSOR (SEE REPLACEMENT
)