2003 LEXUS LS430 Combination

CIRCUIT DESCRIPTION
The BRAKE warning light comes on when the brake fluid is insufficient, the parking brake is applied or the
EBD is defective.
The skid control ECU is connected to the combination meter via CAN and Multiplex communications.
The pad wear indicator is installed to the brake pad (right side).
If the wear indicator wire is open, "Brake Wear" appears on the multi-information display, which indicates that
the pad must be replaced.
WIRING DIAGRAM

INSPECTION PROCEDURE
HINT:
When releasing the parking brake, set the chocks to hold the vehicle for safety.
Check that "Brake Wear" does not appear on the multi-information display.
If it appears, check that brake pad thickness and replace the pad as necessary.
1.CHECK BRAKE FLUID LEVEL IN RESERVOIR
a. Check that the brake fluid level is proper.
OK: Go to next step
Brake fluid level is proper.
NG: ADD BRAKE FLUID
OK: Go to next step
2.CHECK DTC
a. Are the DTC recorded for ABS, VSC, CAN and/or Multiplex communication system?
OK: Go to next step
DTC OUTPUT DESCRIPTION
B: REPAIR CIRCUIT INDICATED BY OUTPUT CODE
A: Go to next step
3.INSPECT BRAKE WARNING LIGHT
a. Connect the hand-held tester to the DLC3.
b. Start the engine.
c. Select the item "BRAKE WARN LIGHT" in the ACTIVE TEST and operate the BRAKE warning
light on the hand-held tester.
VEHICLE CONDITION / TEST DETAILS
d. Check that "ON" and "OFF" of the BRAKE warning light are indicated on the combination meter
when usin
g the hand-held tester.
DTC is not outputA
DTC is outputB
ItemVehicle Condition / Test DetailsDiagnostic Note
BRAKE WRN LIGHTTurns BRAKE warning light ON / OFFObserve combination meter

Fig. 126: Inspecting Pad Wear Indicator Wire Assy
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Standard:
TESTER CONNECTION SPECIFIED CONDITION
REAR:
HINT:
Check that there are no scratches or cracks on the pad wear indicator.
a. Remove the rear wheel RH.
b. Disconnect the pad wear indicator connector.
c. Measure the resistance according to the value (s) in the table below.
Standard:
TESTER CONNECTION SPECIFIED CONDITION
NG: REPLACE PAD WEAR INDICATOR WIRE ASSY
OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
The skid control ECU detects the TRAC control main switch ON/OFF signal and turns the TRAC OFF light
on/off.
When the TRAC control switch is pressed, the TRAC control does not operate and the TRAC OFF light comes
on.
The skid control ECU connected to the combination meter via CAN and MPX communications.
Tester ConnectionSpecified Condition
Terminal a - Terminal bBelow 1 ohms
Terminal a - Body ground1 Mohms or higher
Tester ConnectionSpecified Condition
Terminal a - Terminal bBelow 1 ohms
Terminal a - Body ground1 Mohms or higher

1.PERFORM ACTIVE TEST BY HAND-HELD TESTER (TRAC OFF INDICATOR LIGHT)
a. Connect the hand-held tester to the DLC3.
b. Start the engine.
c. Select the item "TRAC OFF LIGHT" in the ACTIVE TEST and operate the TRAC OFF indicator
light on the hand-held tester.
VEHICLE CONDITION / TEST DETAILS
d. Check that "ON" and "OFF" of the TRAC OFF indicator light are indicated on the combination
meter when using the hand-held tester.
OK: Go to next step
Turn the TRAC OFF indicator light on or off in accordance with the hand-held tester.
NG: Go to step 5
OK: Go to next step
2.INSPECT MULTIPLEX COMMUNICATION SYSTEM
a. Is the DTC output for Multiplex communication system?
Result:
DTC OUTPUT DESCRIPTION
B: REPAIR MULTIPLEX COMMUNICATION SYSTEM (SEE DIAGNOSTIC TROUBLE
CODE CHART )
A: Go to next step
3.INSPECT CAN COMMUNICATION SYSTEM
a. Is the DTC output for CAN communication system?
Result:
DTC OUTPUT DESCRIPTION
ItemVehicle Condition / Test DetailsDiagnostic Note
VSC / TRAC OFF INDTurns VSC / TRAC OFF indicator ON / OFFObserve combination meter
DTC is not outputA
DTC is outputB
DTC is not outputA
DTC is outputB

Fig. 129: Identifying Skid Control ECU Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: Go to next step
6.INSPECT COMBINATION METER ASSEMBLY (SEE PROBLEM SYMPTOMS TABLE
)
NG: REPAIR OR REPLACE COMBINATION METER ASSEMBLY
OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
The SLIP indicator blinks during TRAC & VSC operation.
The skid control ECU is connected to the combination meter via CAN and MPX communications.
WIRING DIAGRAM

a. Connect the hand-held tester to the DLC3.
b. Start the engine.
c. Select the item "SLIP INDI LIGHT" in the ACTIVE TEST and operate the SLIP indicator light on
the hand-held tester.
VEHICLE CONDITION / TEST DETAILS
d. Check that "ON" and "OFF" of the SLIP indicator light are indicated on the combination meter
when using the hand-held tester.
OK: Go to next step
Turn the SLIP indicator light on or off in accordance with the hand-held tester.
NG: Go to step 2
OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)
2.INSPECT MULTIPLEX COMMUNICATION SYSTEM
a. Is the DTC output for Multiplex communication system?
Result:
DTC OUTPUT DESCRIPTION
B: REPAIR MULTIPLEX COMMUNICATION SYSTEM (SEE DIAGNOSTIC TROUBLE
CODE CHART )
A: Go to next step
3.INSPECT CAN COMMUNICATION SYSTEM
a. Is the DTC output for CAN communication system?
Result:
DTC OUTPUT DESCRIPTION
ItemVehicle Condition / Test DetailsDiagnostic Note
SLIP INDI LIGHTTurns SLIP indicator light ON / OFFObserve combination meter
DTC is not outputA
DTC is outputB
DTC is not outputA

B: REPAIR CAN COMMUNICATION SYSTEM (SEE PRECAUTION )
A: Go to next step
4.INSPECT COMBINATION METER ASSEMBLY (SLIP INDICATOR LIGHT) (SEE PROBLEM
SYMPTOMS TABLE )
NG: REPAIR OR REPLACE COMBINATION METER ASSEMBLY
OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
The skid control buzzer sounds and VSC warning (Multi-information display) comes ON during VSC
operation.
WIRING DIAGRAM
DTC is outputB

Fig. 6: Air Conditioning System Diagram (2 Of 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
1.GENERAL
a. The air conditioning system has the following features:
In compliance with the temperature set at the temperature control switch, the neural network
control calculates the outlet temperature based on the input signals from various sensors. In
addition, corrections in accordance with the signals from the evaporative temperature sensor
and the water temperature sensor are added to control the outlet air temperature.
Controls the front and rear blower motors in accordance with the airflow volume that has
been calculated by the neural network control based on the input signals from various
sensors.
Automatically switches the outlets in accordance with the outlet mode ratio that has been
calculated by the neural network control based on the input signals from various sensors.
Automatically controls the air inlet control damper in accordance with the airflow volume
that has been calculated by the neural network control.
Turns the compressor on/off and controls the discharge capacity based on the signals from
various sensors.
Based on the signals from the ambient temperature sensor, this control calculates the outside
temperature, which is then corrected in the air conditioner ECU, and shown in the multi-
information display in the combination meter.
Switched the rear defogger and outside rear view mirror heaters on for 15 minutes when the
rear defogger switch is switched on. Switched them off if the switch is pressed while they are
operating.
Controls the orientation and the angle of the front center register based on the input signals
from various sensors and on the outlet mode.
Determines whether the clean air filter (for the front A/C) is clogged by monitoring the air
inlets, and airflow volume.
The A/C amplifier automatically controls the air inlets based on the signals from the smog
ventilation sensor.
Improves the air quality by linking the air inlet control damper and the blower motor (for the
rear A/C and air purifier), based on the signals from the exhaust gas sensor and the smoke
sensor.
Checks the sensors in accordance with operation of the air conditioner switches.
2.MODEL POSITION AND DAMPER OPERATION