Toyota Land Cruiser 100/Amazon, Lexus LX 470

since 1997 of release

Repair and car operation

System of anti-blocking of brakes (ABS) – the general information and codes of malfunctions

General information

Typical scheme of an arrangement of the ABS components

Electronic ABS control unit (ECU)

ECU of ABS system is fixed under a forward overlay of a threshold of the right door.

ECU traces speed of rotation of each of car wheels, being guided by arriving signals from wheel sensors. When at emergency braking any of wheels it starts to be blocked prematurely, ECU gives out command for activation of the electromagnetic valve placed in the hydraulic modulator which, working, opens the corresponding site of a brake contour, letting out from it a part of working liquid in the tank and, respectively, reducing working pressure. As soon as speeds of rotation of wheels are equalized, the valve is closed again and pressure continues to rise. The cycle lasts fractions of a second on each of wheels and repeats until braking will not be complete. The design of system allows to correct pressure in hydraulic contours of each of four wheels. Actually the scheme of functioning of ABS is much more difficult, than it can seem, therefore originators of the real Management do not recommend to owners of cars to make attempt of independent performance of repair of system. In case of malfunctions it will be most reasonable to address to specialists of car-care center.

Hydraulic modulator

The modulator is established in an impellent compartment and equipped with the electromagnetic valve of adjustment of hydraulic pressure working at the command of ECU in contours of brake system.

Wheel sensors

Each of wheels is equipped with the individual sensor of turns. The sensor consists of a rotor (a ring with teeth evenly located on its perimeter) and a sensitive element in the form of the podmagnichenny coil. The sensitive element of the sensor fixes the moments of passing of teeths of a rotor by it and will transform received information to the electric signals which are continuously transferred to the module of management of ABS. By results of processing of arriving signals of ECU receives information on relative speed of rotation of each of wheels. While all four wheels rotate with identical frequency, ABS stays in a passive condition. As soon as any of wheels starts to be blocked, the control unit fixes change of an entering signal and develops command for operation of the modulator which is instantly dumping pressure of hydraulic liquid in the brake mechanism of the corresponding wheel.

Sensor switch of stoplights

By the signals arriving from the sensor switch of stoplights of ECU determines the moment when the driver squeezes out a pedal of a foot brake, at once activating ABS.

Diagnostics and regenerative repair

If built in in the car dashboard the control lamp of ABS lights up and continues to burn during movement, first of all make sure that the parking brake is completely released, and the brake system functions regularly. If all in norm, therefore, was ABS refusal. Thus in memory of ECU the malfunction code should be brought. At diagnostics and reading of codes of malfunctions the warning bulb on the dashboard will blink. In the presence of several codes, their indication will be begun with smaller number on increasing, regardless of time of their receipt. At car movement codes of malfunction are not displayed. Carry out visual survey:

1. Check a condition of brake supports and wheel cylinders;
2. Check a condition and reliability of fastening of contact R
3. азъемов electroconductings of ECU and wheel sensors (see. Onboard electric equipment);
4. Check the corresponding safety locks (see. Onboard electric equipment).

Regenerative repair of ABS falls outside the limits qualification of the average amateur mechanic.

Reading and deleting of codes of malfunctions