Lexus SC300 / Lexus SC400. Manual — part 268

OK

NG

OK

NG

INSPECTION PROCEDURE

1

Check voltage between terminal 1 of ABS motor relay and body ground.

C

OK

P

Remove ABS motor relay from R/B No. 6.

Measure voltage between terminal 1 of ABS motor relay
and body ground.

Voltage:

10 – 14 V

Check and repair harness or connector

2

Check continuity between terminal 2 of R/B No. 6 (for ABS motor relay) and terminal MT of ABS
(& TRAC) ECU.

C

OK

Hint

Check continuity between terminal 2 or R/B No. 6 (for
ABS motor relay) and terminal MT of ABS (& TRAC)
ECU.

Continuity

There is a resistance of 4 – 6 between terminals BM and
MT for ABS actuator.

Repair or replace harness or ABS actuator.

BR–100

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

OK

NG

OK

NG

3

Check ABS solenoid relay.

C

OK

P

OK

C

Remove solenoid relay from R/B No. 6

Check continuity between each pair of terminal of motor
relay shown below.

1.

Apply battery voltage between terminals 3 and 4.

2.

Check continuity between terminals shown below.

Replace ABS motor relay.

4

Check for open and short in harness and connector between ABS motor relay and ABS (&
TRAC) ECU (See page

IN–33

).

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.

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

BR–101

DTC

15, 16 TRAC Solenoid Relay Circuit

CIRCUIT DESCRIPTION

This relay circuit supplies power to each traction actuator solenoid.When the ignition switch is turned on, the
relay goes on.

DTC No.

DTC Detecting Condition

Trouble Area

15

Conditions (1) through (3) continue for 0.2 sec.or more:

(1) TRAC solenoid relay (TSR) terminal voltage: Bat-

tery positive voltage

(2) All TRAC actuator solenoid: OFF(3) All TRAC ac-

tuator solenoid monitor voltage (in ECU): 0V

TRAC solenoid relay

Open or short in TRAC solenoid relay circuit

ECU

16

Conditions (1) through (3) continue for 0.2 sec.or more:

(1) TRAC solenoid relay (TSR) terminal voltage: 0V

(2) All TRAC actuator solenoid: OFF

(3) TRAC actuator solenoid monitor voltage (in ECU):

Battery positive voltage

TRAC solenoid relay

B+ short in TRAC solenoid relay circuit

ECU

Fail safe function:

If trouble occurs in this relay circuit, the ECU cuts off the current to the ABS and TRAC
solenoid relays and prohibits ABS and TRAC control.

DIAGNOSTIC CHART

DIAGNOSTIC CHART

BR–102

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

WIRING DIAGRAM

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

BR–103