TOYOTA PREVIA 91-97 REPAIR MANUAL

BRAKES 9-33

ANTI-LOCK BRAKE SYSTEM

General Information

» See Figure 126

The ABS is a brake system which controls the wheel cylinder hydraulic
pressure of all four wheels during sudden braking and braking on slippery

road surfaces, prevent the wheels from locking. This ABS provides the fol-

lowing benefits:

1. Enables steering round an obstacle with a greater degree of certainty
   even when panic braking.


2. Enables stopping in a panic brake while keeping effect upon stability
   and steerability to a minimum, even on curves.

(6) ABS ECU

(3) ABS

Actuator

Rear Sensor Rotor (LH)

'2) Rear Speed Sensor (RH)

Rear Sensor Rotor (RH)

(T) Front Speed Sensor

(RH)

Front Sensor Rotor Front Sensor Rotor (LH)

(RH)

0 Front Speed Sensor (LH)

COMPONENTS FUNCTION

No.

1 2 3 4 5 6

Components

Front Speed Sensor

Rear Speed Sensor

ABS Actuator

Deceleration Sensor

(For 4WD model)

ABS Warning Light

ABS ECU

Function

Detects the wheel speed of each of the left and right front wheels from the

rotation of the sensor rotor.

Detects the wheel speed of each of the left and right rear wheels from the

rotation of the sensor rotor.

Controls the brake fluid pressure to each disc brake cylinders through signals

from the ECU.

Detects the deceleration speed of the vehicle and sends a signal accordingly

to the ABS ECU.

Lights up to alert the driver when trouble has occurred in the Anti-Lock Brake

System.

According the wheel speed signals from the each sensor, it calculates accelera-

tion, deceleration and slip values and sends signals to the actuator to control

brake fluid pressure.

Fig. 126 ABS system component locations and functions