Lexus SC300 / Lexus SC400. Service manual — part 271

OK

NG

OK

NG

INSPECTION PROCEDURE

1

Check ABS actuator solenoid.

C

OK

Hint

Hint

OK

C

Check continuity between terminal

4 and

1, 3, 4, 6 of the ABS actuator connector.

Continuity

Resistance of each solenoid coil is 1.2

.

Check continuity between terminal

2 and

1, 4, 5, 6 of the ABS actuator connector.

Continuity

Resistance of each solenoid coil is 1.2

.

Replace ABS actuator.

2

Check for open and short in harness and connector between ABS (& TRAC) ECU and actuator
(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.

BR–112

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

–MEMO–

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

BR–113

DTC

25, 26,

27

TRAC Actuator Solenoid Circuit

CIRCUIT DESCRIPTION

The TRAC actuator solenoid operates in accordance with signals from the ECU, changing TRAC to the normal,
pressure increase, pressure reduction or holding mode.

DTC No.

DTC Detecting Condition

Trouble Area

25

Conditions (1) and (2) continue for 0.05 sec. ormore:

(1) TRAC solenoid relay (TSR) terminalvoltage: Bat-

tery positive voltage

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

TRAC actuator

Open or short in SMC circuit

ECU

26

Conditions (1) and (2) continue for 0.05 sec. ormore:(1)

TRAC solenoid relay (TSR) terminalvoltage: Battery

positive voltage(2) Voltage of ABS & TRAC ECU termi-

nalSAC: 0V

TRAC actuator

Open or short in SAC circuit

ECU

27

Conditions (1) and (2) continue for 0.05 sec. ormore:(1)

TRAC solenoid relay (TSR) terminalvoltage: Battery

positive voltage(2) Voltage of ABS (& TRAC) ECU ter-

minal SRC: 0V

TRAC actuator

Open or short in SRC circuit

ECU

Fail safe function:

If trouble occurs in this solenoid 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–114

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

WIRING DIAGRAM

–

BRAKE SYSTEM

ANTI–LOCK BRAKE SYSTEM (ABS)

BR–115