2003 LEXUS LS430 Diagram AC

Fig. 65: DTC U1102 Problem Symptom Diagnostic Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
WIRING DIAGRAM
Fig. 66: Wiring Diagram
- Lost Communication With Radar Sensor
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
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
Tester connectionConditionSpecified value
D2-23 (LRRD) - M7-4 (LRRD)AlwaysBelow 1 ohms
D2-13 (IGB) - M7-5 (IGB)AlwaysBelow 1 ohms
D2-23 (LRRD) - Body groundAlways10 kohms or higher
D2-13 (IGB) - Body groundAlways10 kohms or higher

Fig. 73: DTC U0123 Problem Symptom Diagnostic Chart
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
HINT:
This circuit uses CAN for communication. Therefore, if there are any malfunctions in the communication
circuit, one or more DTCs in the CAN communication system is/are output.
1.GO TO CAN COMMUNICATION SYSTEM (SEE PRECAUTION
)
CIRCUIT DESCRIPTION
<0037004b004c005600030046004c005500460058004c005700030053005500520059004c004700480056000300530052005a004800550003005700520003005200530048005500440057004800030057004b00480003004600550058004c00560048000300
4600520051005700550052004f00030028002600380003000b[distance control ECU).
The distance control ECU determines the vehicle that you are following based on data from the laser sensor and
then decides how much acceleration and/or deceleration is needed to maintain the set distance. It also requests
the skid control ECU to apply braking and sound the buzzer.
WIRING DIAGRAM

Fig. 74: Wiring Diagram - Distance Control ECU Power Source Circuit
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.INSPECT CRUISE CONTROL ECU ASSY (DISTANCE CONTROL ECU)
a. Disconnect the cruise control ECU (distance control ECU) connector.
b. Measure the voltage according to the value(s) in the table below.
Standard:
CRUISE CONTROL ECU TERMINALS VOLTAGE SPECIFICATION

CIRCUIT DESCRIPTION
This circuit provides power to operate the millimeter wave radar sensor.
The millimeter wave radar sensor emits radar beams towards an object in front and measures the distance and
direction of the object by receiving the beam reflections. Based on the reflections, the sensor calculates the
difference in speed between your own vehicle and an object in front. This data is transmitted to the cruise
control ECU (distance control ECU).
HINT:
The millimeter wave radar sensor monitors the radar emission and reception by itself. This DTC is detected
when it cannot monitor.
When rain drops or snowflakes strike the radar sensor face, the distance between the vehicle in front and your
own vehicle cannot be measured correctly.
The dynamic radar cruise control system functions by detecting the reflector of the vehicle directly in front.
In the following cases, the system may not be able to detect the vehicle in front and may not properly maintain
the correct vehicle-to-vehicle distance.
The vehicle in front is a tall trailer.
Emissions from the vehicle in front or from other lanes are heavy.
WIRING DIAGRAM

Fig. 76: Wiring Diagram - Sensor Power Source Circuit
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.INSPECT MILLIMETER WAVE RADAR SENSOR ASSY
a. Disconnect 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
NG: Go to step
Tester connectionConditionSpecified value
M7-5 (IGB) - Body groundIgnition SW ON10 to 14V

The dynamic laser cruise control system has two cruise control modes: the constant speed control mode and
vehicle-to-vehicle distance control mode.
The vehicle-to-vehicle distance control mode is always selected when starting up the dynamic radar
cruise control system.
The operation of the constant speed control mode is the same as that for the conventional type cruise
control system.
WIRING DIAGRAM
Fig. 82: Wiring Diagram
- Cruise Control Switch Circuit
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.READ VALUE OF HAND-HELD TESTER
a. Connect the hand-held tester to the DLC3.
b. Turn the ignition switch to the ON position.
c. Accordin
g to the display on the tester, read the "DATA LIST".

A wiper switch signal is sent to the distance control ECU via CAN and BEAN. Therefore if there are any
malfunctions in this circuit, check for DTCs in the CAN communication and multiplex communication systems.
When the wiper is in the HI mode, the dynamic radar cruise control is automatically cancelled and goes into the
standby mode.
INSPECTION PROCEDURE
1.INSPECT WIPER AND WASHER SYSTEM (SEE INSPECTION
)
OK:
Wiper function is normal.
NG: GO TO WIPER AND WASHER SYSTEM (SEE HOW TO PROCEED WITH
TROUBLESHOOTING )
OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN DIAGNOSTIC TROUBLE
CODE CHART
CIRCUIT DESCRIPTION
This circuit outputs trouble codes on the multi-information display in the combination meter when terminals TC
and CG of the DLC3 are connected.
WIRING DIAGRAM

Fig. 89: Wiring Diagram - Diagnosis Circuit
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
HINT:
When a particular warning light stays blinking, a ground short in the wiring of terminal TC of the DLC3 or an
internal ground short in the relevant ECU is suspected.
INSPECTION PROCEDURE
1.CHECK HARNESS AND CONNECTOR (TC of DLC3 - ECM)
a. Disconnect the E2 connector from the ECM.
b. Measure the resistance according to the value(s) in the table below.
Standard:
ECM CONNECTOR TERMINALS RESISTANCE
Fig. 90: Identifying DLC3 Connector (TC) Terminals

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Tester connectionConditionSpecified condition
TC (E2-3) - TC (D1 - 13)AlwaysBelow 1 ohms