engine LEXUS LS430 2003 Factory User Guide

OK: Go to next step
The same DTC is recorded.
NG: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS
TABLE
OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
The ABS motor relays consist of 2 relays are included in the engine room No.3 R/B.
The ABS cut relay is turned on after turning the ignition switch to the ON position. If the DTCs in the
ABS pump motor circuit are memorized, the ABS cut relay cuts off the power supply to the ABS motor
relay and performs the fail safe.
While any of the ABS, BA, TRAC and VSC is operating, the skid control ECU (included in the actuator)
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If the voltage applied to the ABS motor relays (+BM) drops below the condition that detects the DTCs
due to the shorta
ge of the battery or alternator output, the DTCs may be memorized.

Fig. 63: ABS Motor Relay Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.PERFORM ACTIVE TEST BY HAND-HELD TESTER (ABS MOTOR RELAY OPERATION)
a. Connect the hand-held tester to the DLC3.
b. Start the engine.
c. Select the ACTIVE TEST mode on the hand-held tester.
d. Check the operation sound of the ABS motor individually when operating it with the hand-held
tester.

NG: CHECK FOR SHORT IN ALL HARNESS AND CONNECTOR CONNECTED TO FUSE
AND REPLACE FUSE
OK: Go to next step
3.CHECK TERMINAL VOLTAGE (ABS MOTOR RELAY 5 TERMINAL OF ENGINE ROOM
NO.3 R/B)
a. Remove the ABS MTR relay from the engine room No.3 R/B.
b. Turn the ignition switch to the ON position.
c. Measure the voltage according to the value (s) in the table below.
Standard:
TESTER CONNECTION SPECIFIED CONDITION
Fig. 65: Identifying ABS MTR Relay Location
Tester ConnectionSpecified Condition
Terminals 5 - Body ground10 to 14V

a. Measure the resistance according to the value (s) in the table below.
Standard:
TESTER CONNECTION SPECIFIED CONDITION
NO: REPLACE ABS CUT RELAY
Fig. 67: Inspecting ABS Cut Relay

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OK: Go to next step
6.CHECK HARNESS AND CONNECTOR (ABS MOTOR RELAY - ABS CUT RELAY)
a. Remove the ABS motor relay and ABS cut relay from engine room R/B.
b. Measure the resistance according to the value (s) in the table below.
Standard:
TESTER CONNECTION SPECIFIED CONDITION
Tester ConnectionConnectionSpecified resistance
3 - 5Always1 Mohms or higher (No continuity)
3 - 5Apply B+ between terminal 1 and 2Below 1 ohms

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: Go to next step
7.CHECK HARNESS AND CONNECTOR (ABS MOTOR RELAY - SKID CONTROL ECU)
a. Disconnect the skid control ECU connector.
b. Measure the resistance according to the value (s) in the table below.
Standard:
TESTER CONNECTION SPECIFIED CONDITION
c. Measure the resistance accordin
g to the value (s) in the table below.
Tester ConnectionSpecified Condition
5 (ABS MOTOR Relay) - 3 (ABS cut relay)Below 1 ohms
Tester ConnectionSpecified Condition
S42-2 (BM) - 3 (Engine room R/B)Below 1 ohms

HINT:
It is suspect that the DTCs output was caused by the poor connection on the connector terminal.
OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)
CIRCUIT DESCRIPTION
If trouble occurs in the engine control system, the ECM transmits the abnormality to the skid control ECU. The
skid control ECU sets this DTC and the skid control ECU prohibits TRAC and VSC control.
DTC DETECTING CONDITION DESCRIPTION
INSPECTION PROCEDURE
1.CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)
a. Using the hand-held tester, check for any momentary interruption in the wire harness and connector
corresponding to a DTC (see CHECK FOR INTERMITTENT PROBLEMS
).
MEASUREMENT ITEM / RANGE (DISPLAY) DESCRIPTION
OK: Go to next step
There are no momentary interruptions.
HINT:
Perform the above inspection before removing the sensor and connector.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (ECM - SKID CONTROL ECU)
OK: Go to next step
2.CHECK DTC FOR ENGINE
a. Check if the normal code is recorded for en
gine control system.
DTC No.DTC Detecting ConditionTrouble Area
C1201/51At the engine speed of 500 RPM, a trouble signal in the engine
control system continues for 5 secs, or more.Engine control
system
ItemMeasurement Item / Range (Display)Normal Condition
EFI COMEFI communication open detectionOPEN: Momentary interruption

NORMAL CODE DESCRIPTION
B: REPAIR ENGINE CONTROL SYSTEM ACCORDING TO DTC OUTPUT
A: REPLACE ECM
CIRCUIT DESCRIPTION
DTC DETECTING CONDITION DESCRIPTION
INSPECTION PROCEDURE
REPLACE ECM
CIRCUIT DESCRIPTION
Brake actuator receives signals from the yaw rate sensor (deceleration sensor) via CAN communication system.
Yaw rate sensor has the built-in deceleration sensor. If there is trouble in the bus lines between yaw rate sensor
(deceleration sensor) and CAN communication system, the DTC codes U0123/62 (yaw rate sensor
communication trouble) and U0124/95 (Deceleration sensor communication trouble) are output. The DTC is
also output when the calibration has not been completed.
Fig. 74: DTC C1210/36 And DTC C1336/39 Detecting Condition And Trouble Area

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Normal CodeA
Malfunction CodeB
DTC No.DTC Detecting ConditionTrouble Area
C1203/53Engine, drive source and destination variations that are sent from the
engine control ECU do not match the ones of the skid control ECU.ECM

When U0121/94, U0123/62, U0124/95 or U0126/63 are output together with C1231/31, inspect and
repair the trouble areas indicated by U0121/94, U0123/62, U0124/95 or U0126/63 first.
When the speed sensor or the yaw rate sensor has trouble, DTCs for the steering angle sensor may be
output even when the steering angle sensor is normal. When DTCs for the speed sensor or yaw rate
sensor are output together with other DTCs for the steering angle sensor, inspect and repair the speed
sensor and yaw rate sensor first, and then inspect and repair the steering angle sensor.
1.CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)
a. Using the hand-held tester, check for any momentary interruption in the wire harness and
connectors between the skid control ECU and steering angle sensor (see CHECK FOR
INTERMITTENT PROBLEMS ).
MEASUREMENT ITEM / RANGE (DISPLAY) DESCRIPTION
OK: Go to next step
There are no momentary interruptions.
NG: REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL ECU -
STEERING ANGLE SENSOR)
OK: Go to next step
2.READ VALUE OF HAND-HELD TESTER (STEERING ANGLE SENSOR VALUE)
a. Connect the hand-held tester to the DLC3.
b. Start the engine.
c. Select the DATA LIST mode on the hand-held tester.
Fig. 77: DATA LIST Mode Description

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
d. Check that the steering angle sensor value of the steering angle sensor observed in the hand-held
tester changes when the steering wheel is moved.
OK: Go to next step
Steering angle value changes.
ItemMeasurement Item / Range (Display)Normal Condition
STEERING SENSteering sensor open detectionOPEN: Momentary interruption

OK: Go to next step
2.INSPECT BATTERY
a. Check the battery voltage.
Standard:
Voltage: 10 to 14 V
NG: INSPECT CHARGING SYSTEM (SEE ON
-VEHICLE INSPECTION )
OK: Go to next step
3.INSPECT SKID CONTROL ECU TERMINAL VOLTAGE (IG1 TERMINAL)
a. Connect the hand-held tester to the DLC3.
b. Start the engine.
c. Select the DATA LIST mode on the hand-held tester.
Fig. 91: DATA LIST Mode Description

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
d. Read the voltage condition output from the ECU displayed on the hand-held tester.
Standard:
"Normal" is displayed.
NG: Go to step 4
OK: REPLACE ABS & TRACTION ACTUATOR ASSY (SEE REPLACEMENT
)
4.INSPECT SKID CONTROL ECU CONNECTOR (GND TERMINAL CONTINUITY)
a. Disconnect the skid control ECU connector.
b. Measure the resistance according to the value (s) in the table below.
Standard:

Fig. 93: Master Cylinder Pressure Sensor Circuit Description
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
Fig. 94: DTC C1246/46 Detecting Condition And Trouble Area

Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.
INSPECTION PROCEDURE
1.READ VALUE OF HAND-HELD TESTER (MASTER CYLINDER PRESSURE SENSOR)
a. Connect the hand-held tester to the DLC3.
b. Start the engine.