LEXUS LS430 2003 Factory Repair Manual

Fig. 19: Problem Symptoms Chart
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1.DISTANCE CONTROL ECU
Fig. 20: Identifying ECU Terminals

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ECU TERMINALS VOLTAGE AND RESISTANCE
a. Reference: waveform 1
HINT:
Terminal: LRDD - GND
Symbols (Terminals No.)Wiring
ColorTerminal
DescriptionConditionSpecified Condition
+B - GND (D2-1 - D2-12)R-B - BRBatteryAlways10 to 14 V
CANH (D2 - 8)LG
CAN
communication
signalCAN
communication
circuit
-
CANL (D2 - 9)L
CAN
communication
signalCAN
communication
circuit
-
SGND - Body ground
(D2-10 - Body ground)BR - Body
groundGroundAlwaysBelow 1 ohms
GND - Body ground (D2-
12 - Body ground)BR - Body
groundGroundAlwaysBelow 1 ohms
IGB - GND (D2-13 - D2-
12)L-O - BRIgnition switch ON
signalIgnition switch OFF
--> ONBelow 1 V --> 10 to
14 V
LRDD - GND (D2-22 -
D2-12)P-L - BRLaser sensor input
signalIgnition switch ONPulse generation (see
waveform 1)
LRRD - GND (D2-23 -
D2-12)L-Y - BRLaser sensor output
signalIgnition switch ONPulse generation (see
waveform 2)

Gauge set: 2 V/DIV, 10 ms/DIV
Condition: Ignition switch ON
Fig. 21: Signal Waveform Graph (Waveform 1)

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b. Reference: waveform 2
HINT:
Terminal: LRRD - GND
Gauge set: 2 V/DIV, 5 ms/DIV
Condition: Ignition switch ON

Fig. 22: Signal Waveform Graph (Waveform 2)
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c.ECM
Fig. 23: Identifying ECM Terminals

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Fig. 24: ECM Terminals Voltage And Resistance Chart
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If the value is not within the standard range, some defects on the vehicle are suspected.
d.LASER SENSOR

Fig. 25: Identifying Laser Sensor Terminals
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LASER SENSOR TERMINALS VOLTAGE AND RESISTANCE
a. Reference: waveform 1
HINT:
Terminal: LRDD - SGND
Gauge set: 1 V/DIV, 2 ms/DIV
Symbols (Terminal No.)Wiring
ColorTerminal
DescriptionConditionSpecified Condition
LGND - Body ground (L1-
1 - Body ground)B-L - Body
groundDistance signalAlwaysBelow 1 ohms
SGND - Body ground (L1-
2 - Body ground)B-R - Body
groundGroundAlwaysBelow 1 ohms
LRDD - SGND (L1-3 -
L1-2)B-O - B-RLaser sensor
output signalIgnition
switch ONPulse generation (see
waveform 1)
LRRD - SGND (L1-4 -
L1-2)B-Y - B-RLaser sensor input
signalIgnition
switch ONPulse generation (see
waveform 2)
IGB - SGND (L1-5 - L1-2)B - B-RPower sourceIgnition
switch ON10 to 14 V

Condition: Ignition switch ON
Fig. 26: Signal Waveform Graph (Waveform 1)

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b. Reference: waveform 2
HINT:
Terminal: LRRD - SGND
Gauge set: 1 V/DIV, 2 ms/DIV
Condition: Ignition switch ON

Fig. 27: Signal Waveform Graph (Waveform 2)
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1.DIAGNOSIS FUNCTION
a. The diagnosis function makes the master warning light and the multi-information display come on,
and the CRUISE main indicator light blinks as shown in the illustration. When a malfunction
occurs in the dynamic laser cruise control system, the DTCs are stored in the ECM.

Fig. 28: Identifying CRUISE Main Indicator Light And Master Warning Light
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Fig. 29: Identifying Blinking Pattern Of CRUISE Main Indicator Light
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2.DESCRIPTION
a. The ECM controls the dynamic laser cruise control system of the vehicle. The data and DTCs
relating to the dynamic laser cruise control system can be read from the DLC3 of the vehicle. If
either DTC or CRUISE OK is not displayed in the multi-information display on the combination
meter when checking for DTCs, there may be a problem with the combination meter or the CAN
communication and multiplex communication system.
Use the hand-held tester to check and solve the problem.
3.CHECK THE DLC3
a. The vehicle's ECM uses ISO 9141-2 for communication. The terminal arrangement of the DLC3
complies with SAE J1962 and matches the ISO 9141-2 format.