2003 LEXUS LS430 lock

1.SYSTEM DESCRIPTION
HINT:
The skid control ECU is a single unit with ABS & TRACTION ACTUATOR.
The skid control ECU also works as a TPMS (Tire Pressure Monitor System) ECU.
The yaw rate sensor and deceleration sensor are combined and in a single unit. This unit
communicates with the skid control ECU through CAN communication.
a. ABS (Anti-lock Brake System)
The ABS helps prevent the wheels from locking when the brakes are applied firmly or when
braking on a slippery surface.
ECUSystem
ECMSkid Control ECUShift Position SignalCAN Communication
System
ECMSkid Control ECUThrottle Position SignalCAN Communication
System
ECMSkid Control ECUEngine Revolution SignalCAN Communication
System
ECMSkid Control ECUWater Temperature Sensor
SignalCAN Communication
System
ECMSkid Control ECUIntake Air Temperature Sensor
SignalCAN Communication
System
Skid Control ECUECMYaw Rate (Deceleration) SignalCAN Communication
System
Skid Control ECUECMVSC Data SignalCAN Communication
System
Skid Control ECUGate Way ECUBrake Warning Lamp ON
SignalBEAN System
Skid Control ECUGate Way ECUABS Warning Lamp ON SignalBEAN System
Skid Control ECUGate Way ECUTRAC OFF Indicator ON
SignalBEAN System
Skid Control ECUGate Way ECUSlip Indicator ON SignalBEAN System
Skid Control ECUGate Way ECUMulti Information display
SignalBEAN System

Fig. 4: ABS & TRACTION Actuator System Description
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Operation description
The skid control ECU detects wheel lock condition by receiving vehicle speed signals from each
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53000300500052005700520055000300440051004700030056[olenoid valve. The pump motor and
solenoid valve avoid wheel lock by controlling the oil pressure of each wheel cylinder.
The ABS warning lamp comes on when the ABS system is malfunctioning.
b. EBD (Electronic Brake force Distribution)
The EBD control utilizes ABS, realizing proper brake force distribution between front and rear
wheels in accordance with driving conditions.
In addition, during cornering braking, it also controls the brake forces of the right and left wheels,
helping to maintain vehicle behavior.

Fig. 19: Identifying VSC Location
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
If the indicator remains on, proceed to troubleshooting for the light circuit below.
TROUBLE AREA REFERENCE
2.SENSOR SIGNAL CHECK BY TEST MODE
HINT:
If the ignition switch is turned from ON to the ACC or LOCK position during test mode, DTC of
Trouble areaSee Procedure
ABS warning light circuitABS WARNING LIGHT CIRCUIT (REMAINS ON)
BRAKE warning light circuitBRAKE WARNING LIGHT CIRCUIT
TRAC OFF indicator light
circuitTRAC OFF INDICATOR LIGHT, TRAC OFF SWITCH
CIRCUIT
SLIP indicator light circuitSLIP INDICATOR LIGHT CIRCUIT

DTC chart of ABS:
DTC C1232/32, C1234/34, C1243/43,
C1244/44, C1245/45, C1381/97
MALFUNCTION IN DECELERATION/YAW RATE
SENSOR, OPEN OR SHORT IN DECELERATION
SENSOR CIRCUIT, MALFUNCTION IN POWER
SUPPLY VOLTAGE YAW/DECELERATION
SENSOR
DTC C1235/35, C1236/36, C1238/38,
C1239/39
FOREIGN MATTER IS ATTACHED ON TIP OF
RIGHT/LEFT FRONT/REAR SENSOR
DTC C1241/41LOW BATTERY POSITIVE VOLTAGE
DTC C1246/46MALFUNCTION IN MASTER CYLINDER
PRESSURE SENSOR
DTC C1249/49OPEN CIRCUIT IN STOP LIGHT SWITCH CIRCUIT
DTC C1251/51PUMP MOTOR IS LOCKED/OPEN CIRCUIT IN
PUMP MOTOR GROUND
DTC C1267/67Brake Pedal Load Sensing Switch

Fig. 48: Inspecting Front Speed Sensor
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
a. Make sure that there is no looseness at the connectors' locking part and connecting part of
connector.
b. Disconnect the speed sensor connector.
c. Measure the resistance according to the value (s) in the table below.
Standard:
TESTER CONNECTION SPECIFIED CONDITION LH:
TESTER CONNECTION SPECIFIED CONDITION RH:
d. Measure the resistance accordin
g to the value (s) in the table below.
Tester ConnectionSpecified Condition
A8-2 (FL+) - A8-1 (FL-)0.6 to 2.5 kohms
Tester ConnectionSpecified Condition
A7-2 (FR+) - A7-1 (FR-)0.6 to 2.5 kohms

VEHICLE CONDITION / TEST DETAILS DESCRIPTION
OK: Go to next step
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5500470011[
NG: Go to step 2
OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)
2.INSPECT FUSE (ABS2 FUSE)
a. Remove the ABS 2 fuse from fusible link block.
b. Measure the resistance according to the value (s) in the table below.
Standard:
ABS 2 FUSE DESCRIPTION
ItemVehicle Condition / Test DetailsVehicle Condition / Test Details
ABS MOT RELAYTurns ABS motor relay / ON or OFFON: Motor relay ON
ABS 2 FuseBelow 1 ohms (Continuity)

Fig. 71: ABS Solenoid Relay Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.INSPECT FUSE (ABS1 FUSE)
a. Remove the ABS 1 fuse from the fusible link block.
b. Measure the resistance according to the value (s) in the table below.
Standard:
ABS 1 FUSE DESCRIPTION
ABS 1 fuseBelow 1 ohms (Continuity)

b. Turn the radio and receiver assy on.
c. Set the radio channels and register them.
d. Turn the ignition switch off.
e. Turn the ignition switch to the ON position.
f. Turn the radio and receiver assy on.
g. Check if the registered memory is deleted or not.
OK:
The registered memory is not deleted.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (DRIVER SIDE J/B - BATTERY)
OK: Go to next step
4.INSPECT FUSE (HEATER)
a. Remove the HEATER fuse from the FL block.
b. Measure the resistance according to the value (s) in the table below.
Standard:
FUSE (HEATER) RESISTANCE
NG: CHECK FOR SHORT IN ALL HARNESSES AND COMPONENTS CONNECTED TO
FAILURE FUSE
Tester itemConditionSpecified condition
HEATER fuseAlwaysBelow 1 ohms