Lexus SC300 / Lexus SC400. Manual - part 269

OK

NG

OK

NG

INSPECTION PROCEDURE

1

Check voltage between terminal 1 of R/B No. 6 (for TRAC solenoid relay) and body ground.

C

OK

P

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

Measure voltage between terminal 1 o R/B No. 6 (for
TRAC solenoid relay) and body ground.

Voltage:

10 – 14 V

Repair or replace harness or connector.

2

Check continuity between terminal 3 of R/B No. 6 (for TRAC solenoid relay) and terminals SAC,
SMC, SRC or ABS & TRAC ECU.

C

OK

Hint

Check continuity between terminal 3 of R/B No. 6 (for
TRAC solenoid relay) and terminals SAC, SMC, SRC of
ABS & TRAC ECU.

Continuity

Resistance of the TRAC actuator solenoid is 2 

.

Repair or replace harness or TRAC actuator.

BR–104

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

OK

NG

OK

NG

3

Check TRAC solenoid relay.

C

OK

P

OK

C

Remove solenoid relay from R/B NO. 6.

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

1.

Apply battery voltage between terminals 4 and 6.

2.

Check continuity between terminals shown below.

Replace TRAC solenoid relay.

4

Check for open and short in harness and connector between TRAC 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–105

DTC

17, 18 TRAC Motor Relay Circuit

CIRCUIT DESCRIPTION

This relay circuit supplies power to the TRAC pump motor. If the accumulator pressure drops, the ECU switches
the motor relay ON and operates the TRAC motor.

DTC No.

DTC Detecting Condition

Trouble Area

17

Conditions (1) through (2) continue for 0.2 sec.or more:

(1) TRAC motor relay (TMR) terminal voltage: Battery

positive voltage

(2) Voltage of ABS & TRAC ECU terminal MTT: 0 V

TRAC motor relay

Open or short in TRAC motor relay circuit

ECU

18

Conditions (1) and (2) continue for 2 sec. ormore:

(1) TRAC motor relay (TSR) terminalvoltage: 0 V

(2) Voltage of ABS & TRAC ECU terminal MTT: Battery

positive voltage

TRAC motor relay

B+ short in TRAC motor relay circuit

ECU

Fail safe function: 

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

DIAGNOSTIC CHART

DIAGNOSTIC CHART

BR–106

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

WIRING DIAGRAM

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

BR–107