Lexus SC300 / Lexus SC400. Manual — part 243

WIRING DIAGRAM

–

BRAKE SYSTEM

TRACTION CONTROL SYSTEM (TRAC)

BR–223

NO

YES

OK

NG

OK

NG

OK

NG

OK

NG

INSPECTION PROCEDURES

1

Is diagnostic trouble code output?

Perform diagnostic trouble code check on page

BR–184

.

Repair circuit indicated by the code output.

2

Check TRAC cut switch

C

OK

P

1.

Remove TRAC cut switch.

2.

Disconnect TRAC cut switch connector.

Measure resistance between terminals 1 and 2 of TRAC
cut switch when TRAC cut switch is on and off.

Replace TRAC cut switch.

3

Check for open and short in harness and connector between terminal CSW of TRAC ECU and
TRAC cut switch and body ground (See page

IN–33

).

Repair or replace harness or connector.

4

Check TRAC OF indicator light.

See combination meter troubleshooting on page

BE–191

.

Repair or replace combination meter.

5

Check for open and short in harness and connector between terminal WT of TRAC ECU and bat-
tery or TRAC solenoid relay (See page

IN–33

).

Repair or replace harness or connector.

Check and replace TRAC ECU.

BR–224

–

BRAKE SYSTEM

TRACTION CONTROL SYSTEM (TRAC)

BR–150

).

BE–163

.

IN–33

).

WIRING DIAGRAM

TRAC Indicator Light Circuit

CIRCUIT DESCRIPTION

The TRAC indicator blinks during TRAC operation.
This indicator is also used for warnings when the trouble occurs and for displaying diagnostic trouble codes.

DIAGNOSTIC CHART

DIAGNOSTIC CHART

–

BRAKE SYSTEM

TRACTION CONTROL SYSTEM (TRAC)

BR–225

BR–160

).

IN–33

).

WIRING DIAGRAM

Tc Terminal Circuit

CIRCUIT DESCRIPTION

By connecting between terminals Tc and E1 of DLC1 or DLC2, the ECU displays the diagnostic trouble
code by blinking the TRAC indicator light.

DIAGNOSTIC CHART

DIAGNOSTIC CHART

BR–226

–

BRAKE SYSTEM

TRACTION CONTROL SYSTEM (TRAC)