LEXUS LS430 2003 Factory Repair Manual

Result:
DTC OUTPUT DESCRIPTION
B: REPAIR CAN COMMUNICATION SYSTEM (SEE PRECAUTION
)
A: 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.CHECK MULTI INFORMATION DISPLAY (VSC WARNING)
a. Connect the hand-held tester to the DLC3 and start the engine.
b. Select the item "VSC WARN LIGHT" in the ACTIVE TEST and operate the VSC warning light on
the hand-held tester.
VEHICLE CONDITION / TEST DETAILS
c. Check that "ON" and "OFF" of the VSC warning light are indicated on the combination meter
when using the hand-held tester.
OK: Go to next step
Turn the VSC warning light ON or OFF in accordance with the hand-held tester.
NG: CHECK AND REPAIR VSC WARNING LIGHT CIRCUIT
OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)
DTC is not outputA
DTC is outputB
DTC is not outputA
DTC is outputB
ItemVehicle Condition / Test DetailsDiagnostic Note
VSC WARN LIGHTTurns VSC warning light ON / OFFObserve combination meter

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

Fig. 120: Brake Warning Light Wiring Diagram (1 Of 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

Fig. 121: Brake Warning Light Wiring Diagram (2 Of 2)
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

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

OK: Go to next step
Turn the BRAKE warning light on or off in accordance with the hand-held tester.
NG: Go to step 4
OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)
4.INSPECT PARKING BRAKE SWITCH ASSY
a. Remove the parking brake switch connector.
b. Measure the resistance according to the value (s) in the table below.
Standard:
TESTER CONNECTION SPECIFIED CONDITION
NG: REPLACE PARKING BRAKE SWITCH ASSY
Tester ConnectionSwitch ConditionSpecified Condition
P3-1 - Ground partReleasedBelow 1 ohms
P3-1 - Ground partPushed in1M ohms or higher

Fig. 122: Inspecting Parking Brake Switch Assy
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: Go to next step
5.CHECK HARNESS OR CONNECTOR (SKID CONTROL ECU - PARKING BRAKE SWITCH)
a. Disconnect the skid control ECU connector and the parking brake switch connector.
b. Measure the resistance according to the value (s) in the table below.
Standard:
TESTER CONNECTION SPECIFIED CONDITION
c. Measure the resistance according to the value (s) in the table below.
Standard:
TESTER CONNECTION SPECIFIED CONDITION
Tester ConnectionSpecified Condition
S42-28 (PKB) - P3-1 (PKB)Below 1 ohms
Tester ConnectionSpecified Condition

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
Fig. 123: Identifying Skid Control ECU Terminals

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: Go to next step
6.INSPECT BRAKE FLUID LEVEL WARNING SWITCH
a. Remove the reservoir tank cap and strainer.
S42-28 (PKB) - Body ground1M ohms or higher

b. Disconnect the brake fluid level warning switch connector.
c. Measure the resistance according to the value (s) in the table below.
Standard:
TESTER CONNECTION SPECIFIED CONDITION
NG: REPLACE BRAKE FLUID LEVEL WARNING SWITCH
Fig. 124: Identifying Brake Fluid Level Warning Switch Terminals

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
OK: Go to next step
7.CHECK HARNESS OR CONNECTOR (BRAKE FLUID LEVEL WARNING SWITCH SKID
CONTROL ECU)
Tester ConnectionSwitch ConditionSpecified Condition
(B1-1) - (B1-2)Float UP1M ohms or higher
(B1-1) - (B1-2)Float DOWNBelow 1 ohms

a. Disconnect the skid control ECU connector and the brake fluid level warning switch connector.
b. Measure the resistance according to the value (s) in the table below.
Standard:
TESTER CONNECTION SPECIFIED CONDITION
c. Measure the resistance according to the value (s) in the table below.
Standard:
TESTER CONNECTION SPECIFIED CONDITION
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
Tester ConnectionSpecified Condition
S42-10 (LBL) - (B1-1)Below 1 ohms
Tester ConnectionSpecified Condition
S42-10 (LBL) - Body ground1 Mohms or higher