Lexus SC300 / Lexus SC400. Service manual - part 272

OK

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OK

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OK

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INSPECTION PROCEDURE

1

Check TRAC actuator solenoid.

C

OK

P

Disconnect TRAC actuator connector.

Check continuity between each terminal of TRAC ac-
tuator shown below.

Replace TRAC actuator.

2

Check for open and short in harness and connector between solenoid relay and ECU (See page
 

IN–33

).

Repair or replace harness or connector.

3

Check for short in harness and connector between SMC and SRC, SAC and SMC, and SAC and
SRC terminals with TRAC actuator and ECU connectors are disconnected.

Repair or replace harness or connector.

If the same code is still output after the diagnostic trouble code is deleted, check the contact condition
of each connection. If the connections are normal, the ECU may be defective.

BR–116

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

–MEMO–

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

BR–117

DTC

31, 32,
33, 34,

35, 36

Speed Sensor Circuit

CIRCUIT DESCRIPTION

The speed sensor detects the wheel speed and sends the ap-
propriate signals to the ECU. These signals are used for control
of both the ABS and TRAC control systems. The front and rear
rotors each have 48 serrations. When the rotors rotate, the
magnetic field emitted by the permanent magnet in the speed
sensor generates an AC voltage. Since the frequency of this
AC voltage changes in proportion to the speed of the rotors
(wheels) the frequency is used by the ECU to detect the speed
of each wheel.

BR3583

BR3582

DTC No.

DTC Detecting Condition

Trouble Area

31, 32,

33, 34

Detection of any of conditions (1) through (3):

(1) At vehicle speed of 10 km/h (6 mph) or more,

pulses are not input for 5 sec.

(2) Momentary interruption of the vehicle speed sen-

sor signal occurs at least 7 times in the time between

switching the ignition switch ON and switching it OFF.

(3) Abnormal fluctuation of speed sensor signals with

the vehicle speed 20 km/h (12 mph) or more.

Right front, left front, right rear and left rear

speed sensor.

Open or short in each speed sensor circuit.

ECU

35

Vehicle speed sensor signal is not input for about 1 sec.

while the left front and right rear with the vehicle speed

sensor signals are being checked IG switch ON.

Open in left front, right rear speed sensor cir-

cuit.

ECU

36

Vehicle speed sensor signal is not input for about 1 sec.

while the right front and left rear vehicle speed sensor

signals are being checked with the IG switch ON.

Open in right front, left rear speed sensor cir-

cuit.

ECU

HINT:

DTC No. 31 is for the right front wheel speed sensor.
DTC No. 32 is for the left front wheel speed sensor.
DTC No. 33 is for the right rear wheel speed sensor.
DTC No. 34 is for the left rear wheel speed sensor.

Fail safe function:

If trouble occurs in the speed sensor circuit, the ECU cuts off current to the ABS

solenoid relay and prohibits ABS control.

BR–118

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

DIAGNOSTIC CHART

DIAGNOSTIC CHART

WIRING DIAGRAM

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

BR–119