sensor LEXUS LS430 2003 Factory Repair Manual

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.

1.DATA LIST
HINT:
From the DATA LIST displayed on the hand-held tester, the value of components such as the switch,
sensor, and actuator can be read without parts removal. Reading the DATA LIST as the first step of
troubleshooting is one way to shorten labor time.
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position.
c. According to the display on the tester, read the "DATA LIST".
CC (ECM):

a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position.
c. According to the display on the tester, perform the "ACTIVE TEST".
HINT:
The ignition switch must be turned to the ON position to proceed to the ACTIVE TEST using the hand-
held tester.
COMBINATION METER ASSY:
ACTIVE TEST DETAIL (COMBINATION METER ASSY)
HINT:
If a trouble code is displayed during the DTC check, check the circuit listed for that code. For details of each
code, refer to the DTC chart below.
DIAGNOSTIC TROUBLE CODE CHART
ItemVehicle Condition / Test DetailsDiagnostic Note
CRUISE INDIC"CRUISE" indicator is ON / OFF-
L-CRUISE DISPGraphic area is ON / OFF((1))
L-CRS CHECK IND"CHECK CRUISE SYSTEM" indicator is
ON / OFF-
L-CRS READY IND"RADAR READY" indicator is ON / OFF-
(1)The entire graphic area in the combination meter will light up.
DTCDescription
DTC P0500, DTC P0503VEHICLE SPEED SENSOR CIRCUIT MALFUNCTION
DTC P0571STOP LIGHT SWITCH CIRCUIT MALFUNCTION
DTC P0607INPUT SIGNAL CIRCUIT MALFUNCTION
DTC P1615, DTC U1101COMMUNICATION ERROR FROM DISTANCE CONTROL ECU
TO ECM
DTC P1616, DTC U0100COMMUNICATION ERROR FROM ECM TO DISTANCE
CONTROL ECU
DTC P1617DISTANCE CONTROL ECU MALFUNCTION
DTC P1630, DTC U0122COMMUNICATION ERROR FROM VSC TO ECM
DTC P1631, DTC U0100COMMUNICATION ERROR FROM ECM TO VSC
DTC P1575WARNING BUZZER MALFUNCTION
DTC P1578BRAKE SYSTEM MALFUNCTION
DTC U0235LOST COMMUNICATION WITH CRUISE CONTROL FRONT
DISTANCE RANGE SENSOR

DTC U1102LOST COMMUNICATION WITH RADAR SENSOR
DTC P1572IMPROPER AIMING OF RADAR SENSOR BEAM AXIS
DTC U0126LOST COMMUNICATION WITH STEERING ANGLE SENSOR
MODULE
DTC U0123LOST COMMUNICATION WITH YAW RATE SENSOR MODULE

CIRCUIT DESCRIPTION
This DTC indicates a malfunction in the ECM.
HINT:
The ECM receives signals from each sensor to control all the functions of the cruise control with the
microcomputer.
When a malfunction is detected, fail-safe remains on until the ignition switch is turned off.
Fig. 52: DTC P0607 Problem Symptom Diagnostic Chart

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INSPECTION PROCEDURE
1.REPLACE ECM (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
The distance control ECU receives information about the area in front of the vehicle from the millimeter wave
radar sensor and then sends a brake control demand signal (deceleration demand) and diagnosis signals, such as
millimeter wave radar sensor grime or millimeter wave radar sensor malfunction, to the ECM.

Fig. 53: DTC P1615 And U1101 Problem Symptom Diagnostic Chart
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INSPECTION PROCEDURE
HINT:
This circuit uses CAN for communication. Therefore, one or more DTCs in the CAN communication system
is/are output if there are any malfunctions in the communication circuit.
1.GO TO CAN COMMUNICATION SYSTEM (SEE PRECAUTION
)
CIRCUIT DESCRIPTION
The ECM receives signals from each sensor and ECU, then sends signals such as the A/T signal, cruise control
<005200530048005500440057004c0052005100030056004c004a00510044004f000f0003004f0052005a0003005600530048004800470003005200530048005500440057004c0052005100030056004c004a00510044004f000f0003004500550044004e00
480003004600520051005700550052004f0003005200530048[ration signal and laser light emission prohibiting
signal, etc. to the distance control ECU.
<0037004b004800030028002600300003004c005600030057004b0048000300520051004f005c000300460052005000530052005100480051005700030057004b004400570003004b0044005600030044000300490058005100460057004c00520051000300
57005200030055004800460052005500470003004400510047[ output the DTCs in the dynamic radar cruise
control system. Therefore if the distance control ECU detects a communication error from the ECM, it sends the
malfunction signal back to the ECM.
Fig. 54: DTC P1616 And U0100 Problem Symptom Diagnostic Chart

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circuit, one or more DTCs in the CAN communication system is/are output.
1.CHECK BRAKE SYSTEM (SEE HOW TO PROCEED WITH TROUBLESHOOTING
)
CIRCUIT DESCRIPTION
The Millimeter wave radar sensor and cruise control ECU (distance control ECU) transmit the data for general
vehicle control and diagnosis function along the communication line.
The Millimeter wave radar sensor transmits information about the vehicle in front to the cruise control ECU
(distance control ECU).
Fig. 59: DTC U0235 Problem Symptom Diagnostic Chart

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WIRING DIAGRAM
Fig. 60: Wiring Diagram
- Lost Communication With Cruise Control Front Distance Range Sensor
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INSPECTION PROCEDURE
1.CHECK WIRE HARNESS AND CONNECTOR (DISTANCE CONTROL ECU - MILLIMETER

WAVE RADAR SENSOR)
a. Disconnect the distance control ECU and millimeter wave radar sensor connectors.
b. Measure the resistance according to the value(s) in the table below.
Standard:
DISTANCE CONTROL ECU AND MILLIMETER WAVE RADAR SENSOR TERMINALS
RESISTANCE SPECIFICATION
Fig. 61: Disconnecting Distance Control ECU Connector

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Tester connectionConditionSpecified value
D2-22 (LRDD) - M7-3 (LRDD)AlwaysBelow 1 ohms
D2-13 (IGB) - M7-5 (IGB)AlwaysBelow 1 ohms
D2-22 (LRDD) - Body groundAlways10 kohms or higher
D2-13 (IGB) - Body groundAlways10 kohms or higher

Fig. 62: Disconnecting Millimeter Wave Radar Sensor Connector
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NG: REPAIR OR REPLACE WIRE HARNESS OR CONNECTOR
OK: Go To Next Step.
2.INSPECT MILLIMETER WAVE RADAR SENSOR ASSY
a. Reconnect the millimeter wave radar sensor connector.
b. Measure the voltage according to the value(s) in the table below.
Standard:
MILLIMETER WAVE RADAR SENSOR TERMINALS VOLTAGE SPECIFICATION

c. Check the signal waveform between terminal LRDD (M7-3) of the millimeter wave radar 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 MILLIMETER WAVE RADAR SENSOR ASSY (SEE ADJUSTMENT
)
Fig. 63: Reconnecting Millimeter Wave Radar Sensor Connector

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Tester connectionConditionSpecified value
M7-5 (IGB) - Body groundIgnition SW ON10 to 14V