2003 LEXUS LS430 Identifying ac

Fig. 15: Identifying Cruise Control Main Switch
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2.INSPECT MODE SWITCH
a. Turn the ignition switch to the ON position.
HINT:
Dynamic laser cruise system is in the default mode.
b. After pushing the ON-OFF button on, push the cruise control main switch to MODE for at least 1
second without any other control. Make sure that only "NORM." and nothing else is indicated on
the display.

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)

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

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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

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.

Fig. 30: Identifying DLC3 Connector Terminals
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DLC3 CONNECTOR TERMINALS RESISTANCE
HINT:
If the displa
y shows "UNABLE TO CONNECT TO VEHICLE" when you have connected the hand-held
Symbols (Terminals No.)Terminal DescriptionConditionSpecified Condition
SIL(7) - SG(5)Bus "+" lineDuring transmissionPulse generation
CG(4) - Body groundChassis groundAlwaysBelow 1 ohms
SG(5) - Body groundSignal groundAlwaysBelow 1 ohms
BAT(16) - Body groundBattery positiveAlways11 to 14 V
CANH(6) - CANL(14)HIGH-level CAN bus lineIG switch OFF54 to 67 ohms
CANH(6) - Battery positiveHIGH-level CAN bus lineIG switch OFF1 Mohms or higher
CANH(6) - CG(4)HIGH-level CAN bus lineIG switch OFF3 kohms or higher
CANL(14) - Battery positiveLOW-level CAN bus lineIG switch OFF1 Mohms or higher
CANL(14) - CG(4)LOW-level CAN bus lineIG switch OFF3 kohms or higher

If a malfunction occurs in the vehicle speed sensors, the stop lamp switch, or other related parts during
cruise control driving, the ECU actuates AUTO CANCEL of the cruise control and blinks the CRUISE
main indicator light. This indicator light informs the driver of the malfunction. At the same time, the
malfunction is stored as a diagnostic trouble code.
Fig. 32: Identifying Blinking Pattern Of CRUISE Main Indicator Light

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1.DTC CHECK
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position.
c. Read the DTCs by following the prompts on the tester screen.
2.DTC CLEAR
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position.
c. Clear the DTCs following the prompts on the tester screen.
HINT:
Refer to the han
d-held tester operators manual for further details.