Lexus SC300 / Lexus SC400. Service manual — part 267

OK

NG

OK

NG

INSPECTION PROCEDURE

1

Check voltage between terminals 1 and 2 of R/B No. 6 (For ABS solenoid relay).

C

OK

P

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

Measure voltage between terminals 1 and 2 of R/B No.
6 (for ABS solenoid relay).

Voltage:

10 – 14 V

Check and repair harness or connector.

2

Check continuity between terminal 3 or R/B No. 6 (for ABS solenoid relay) and terminal AST of
ABS (& TRAC) ECU.

C

OK

Hint

Check continuity between 3 of R/B No. 6 (for ABS sole-
noid relay) and terminal AST of ABS (& TRAC) ECU.

Continuity

There is a resistance of 4 ~ 6

between terminals BS

and AST of ABS actuator.

Repair or replace harness or ABS actuator.

BR–96

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

OK

NG

OK

NG

3

Check ABS solenoid relay.

C

OK

P

C

OK

Remove solenoid relay from R/B No. 6.

Check continuity between each terminal of ABS sole-
noid relay shown below.

1.

Apply battery voltage between terminals 4 and 6.

2.

Check continuity between each terminal of ABS so-
lenoid relay shown below.

Replace ABS solenoid relay.

4

Check for open and short in harness and connector between ABS solenoid 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–97

DTC

13, 14 ABS Motor Relay Circuit

CIRCUIT DESCRIPTION

The ABS motor relay supplies power to the ABS pump motor. While the ABS is activate the ECU switches the
motor relay ON and operates the ABS pump motor.

DTC No.

DTC Detecting Condition

Trouble Area

13

Conditions (1) and (2) continued for 0.2 sec. or more:

(1) ABS motor relay (MR) terminal voltage: Battery

positive voltage

(2) Motor relay monitor (MT) terminal voltage: 0V

ABS motor relay

Open or short in ABS motor relay circuit

ECU

14

Conditions (1) and (2) continued for 4 sec. or more:

(1) ABS motor relay (MR) terminal voltage: 0V

(2) Motor relay monitor (MT) terminal voltage:

Battery positive voltage

ABS motor relay

B+ short in ABS motor relay circuit.

ECU

Fail safe function: If trouble occurs in the motor relay circuit, the ECU cuts off the current to the solenoid

relay and prohibits ABS control.

DIAGNOSTIC CHART

DIAGNOSTIC CHART

BR–98

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

BR–99

WIRING DIAGRAM