2003 LEXUS LS430 traction control

Fig. 118: Identifying Skid Control ECU Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
If the ECU stores DTC, the VSC warning light comes on in the combination meter.
The skid control ECU is connected to the combination meter via CAN and MPX communications.
WIRING DIAGRAM

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

B: REPAIR CAN COMMUNICATION SYSTEM (SEE PRECAUTION )
A: Go to next step
4.INSPECT TRACTION CONTROL SWITCH
a. Remove the TRAC control switch.
b. Disconnect the TRAC control switch connector.
c. Measure the resistance according to the value (s) in the table below.
Standard:
TESTER CONNECTION SPECIFIED CONDITION
NG: REPLACE TRACTION CONTROL SWITCH
Tester ConnectionSwitch ConditionSpecified Condition
T7-8 (+) - T7-6Pushed in (ON)Below 1 ohms
T7-8 (+) - T7-6Released (OFF)1 Mohms or higher

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

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

VEHICLE CONDITION / TEST DETAILS
d. Check that skid control buzzer sounds by operating with the hand-held tester.
OK: Go to next step
The skid control buzzer sounds in accordance with operation of the hand-held tester.
NG: Go to step 2
OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)
2.INSPECT SKID CONTROL BUZZER
a. Disconnect the skid control buzzer connector.
b. Apply a battery positive voltage to terminals 1 and 2 of the skid control buzzer connector, and
check that the buzzer sounds.
OK: Go to next step
The skid control buzzer sound is heard.
NG: REPLACE SKID CONTROL BUZZER
ItemVehicle Condition / Test DetailsDiagnostic Note
VSC / BR WARN BUZTurns VSC / BRAKE warning buzzer ON / OFFBuzzer can be heard

Fig. 140: Identifying Skid Control ECU Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)

Fig. 142: Identifying Skid Control ECU Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)