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 SPECIFICATION
Symbols (Terminals
No.)Wiring
ColorTerminal DescriptionConditionSpecified
Condition
+B - GND (D2-1 - D2-
12)R-B - BRBatteryAlways10 to 14V
CANH (D2 - 8)LGCAN communication
signalCAN
communication
circuit
-
CANL (D2 - 9)LCAN 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 1ohms
IGB - GND (D2-13 -
D2-12)L-0 - BRIgnition switch ON signalIgnition switch OFF
--> ONBelow 1 V --> 10
to 14V
LRDD - GND (D2-22 -
D2-12)P-L - BRMillimeter wave radar
sensor input signalIgnition switch ONPulse generation
(see waveform 1)
LRRD - GND (D2-23 -
D2-12)L-Y - BRMillimeter wave radar
sensor output signalIgnition switch ONPulse generation
(see waveform 2)

a. Reference: waveform 1
HINT:
Terminal: LRDD - GND
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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2.ECM
Fig. 23: Identifying ECM Connector Terminals

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Fig. 24: ECM Connector 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.
3.MILLIMETER WAVE RADAR SENSOR

Fig. 25: Identifying Millimeter Wave Radar Sensor Connector Terminals
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MILLIMETER WAVE RADAR SENSOR CONNECTOR TERMINALS VOLTAGE AND
RESISTANCE SPECIFICATION
a. Reference: waveform 1
HINT:
Terminal: LRDD - SGND
Symbols (Terminal No.)Wiring
ColorTerminal DescriptionConditionSpecified Condition
LGND - Body ground
(M7-1 - Body ground)B-L -Body
groundGround (Distance signal)AlwaysBelow 1 ohms
SGND - Body ground
(M7-2 - Body ground)B-R - Body
groundGroundAlwaysBelow 1 ohms
LRDD - SGND (M7-3 -
M7-2)B-O - B-RMillimeter wave radar
sensor output signalIgnition
switch ONPulse generation (see
waveform 1)
LRRD - SGND (M7-4 -
M7-2)B-Y - B-RMillimeter wave radar
sensor input signalIgnition
switch ONPulse generation (see
waveform 2)
IGB - SGND (M7-5 - M7-
2)B - B-RPower sourceIgnition
switch ON10 to 14V

Gauge set: 1 V/DIV, 2 ms/DIV
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 radar cruise control system, the DTCs are stored in the ECM.

Fig. 28: Identifying Master Warning Light And CRUISE Main Indicator 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 radar cruise control system of the vehicle. The data and DTCs
relating to the dynamic radar 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.