Lexus SC300 / Lexus SC400. Manual - part 274

OK

NG

OK

NG

3

Check continuity between terminal GND of ABS (& TRAC) ECU connector and body ground.

C

OK

Measure resistance between terminals GND or ABS (&
TRAC) ECU connector and body ground.

Resistance:

1 



 or less

Repair or replace harness or connector.

4

Check ECU–IG fuse.

C

OK

P

Remove ECU–IG fuse from J/B No. 1.

Check continuity of ECU–IG fuse.

Continuity

Check for short in all the harness and components con-
nected to ECU–IG fuse (See attached wiring diagram).

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

IN–33

).

BR–124

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

WIRING DIAGRAM

DTC

51

ABS Pump Motor Lock

CIRCUIT DESCRIPTION

DTC No.

DTC Detecting Condition

Trouble Area

51

Pump motor is not operating normally duringinitial

check.

ABS pump motor

Fail safe function: 

If trouble occurs in the ABS pump motor, the ECU cuts off the current to the solenoid

relay and prohibits ABS control.

DIAGNOSTIC CHART

DIAGNOSTIC CHART

See inspection of ABS pump motor (See page 

BR–65

 or 

BR–68

).

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

BR–125

IN–3

3

DTC

53

TRAC–Pump Motor Lock

CIRCUIT DESCRIPTION

DTC No.

DTC Detecting Condition

Trouble Area

53

 TRAC pump motor is locked

 Open for TRAC pump motor ground.

TRAC pump motor

Harness or connector between TRAC pump&

motor and body ground.

TRAC Actuator

ABS & TRAC ECU

DIAGNOSTIC CHART

DIAGNOSTIC CHART

BR–126

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

WIRING DIAGRAM

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

BR–127