printable version

ABS control unit

The braking system with ABS car

ABS control unit performs the following functions:

- Controls the ABS;
- Calculates the speed of the car;
- Carries out a self-test of the system: a self-diagnostic fault codes, and safety functions shall be stored in two separated microprocessors.

ABS control unit continuously checks the blocking of each wheel, and controls each valve to regulate the pressure of the brake fluid, if necessary.

ABS control unit also checks that the components are working properly and off the ABS in case of failures.
Then the brake system works like a standard braking system.

RPM Sensor

The speed sensor detects the rotation of the wheel and comprises a permanent magnet and coil. The sensors of the front wheels receive information from the toothed rotor disposed on the drive shafts.

When passing near the sensor rotor teeth, changing the magnetic field sensor, whereby the generated voltage pulse.

This voltage is proportional to the wheel speed and can be measured.

Indicator lamps ABS and EBD are located in the instrument cluster.

Control lamp ABS:

1) On for 3 seconds after the ignition is switched on then goes out.
2) Goes off when the engine is started.
3) If the lamp stays on, it means there are violations in the ABS.
4) The lamp is lit during the self-diagnostics.
5) If the warning light comes on intermittently, then to ABS there are infringements and operation systems of the car is carried out in such a way as if the car no ABS and TCS.
6) The lamp is lit when disconnecting the electrical connector from the control unit ECU.

The indicator lamp EBD (electronic brake force distribution)

1) Lights after ignition.
2) Goes off when the engine is started.
3) Lights when tightening the handbrake lever.
4) On the low brake fluid level.
5) Lights when not working electronic brake force distribution EBD:
- A fault in the solenoid valve;
- If the fault is more than one sensor;
- Malfunction of the control unit ECU;
- In excess voltage.

Hydraulic control unit (HCU)

Hydraulic control unit (HCU) consists of a pump with an electric motor and the valve block to control the pressure ABS.

The sensor is located in the motor and pump unit transmits the output signal ABS, which defines the performance of the pump.

The hole diameter of the pipe supplying the brake fluid of the front brake: 4.8 mm
The hole diameter of the pipe supplying the brake fluid Rear brake: 4.8 mm

The pump with two circuits provide the required pressure and flow valves distribute the pressure transmitted to the wheel brake.

A - front right inlet valve; C - left rear inlet valve; C - rear right inlet valve; D - front left inlet valve; E - front right outlet valve; F - rear left exhaust valve; G - Rear right outlet valve; H - front left outlet valve; M - engine; N - engine (GND).

ABS self-diagnosis

ABS control unit begins to perform self-diagnostic function after switching on the ignition. ABS control unit detects a fault for each circuit component and comparing the state of the system with a limited set of conditions in the block of management ABS. ABS control unit stores a fault code and then displays a diagnostic tool in the form of code, referred to four digits.

Check self-diagnosis codes

PERFORMANCE ORDER

1. Turn the ignition key to the OFF position and connect the scan tool to the diagnostic socket, located near the vacuum amplifier in the engine compartment. 2. Turn the ignition switch to the ON position and set the device to your car model and model diagnostic tool. 3. Select the parameters to be checked after initialization block. 4. Click the check codes ?��1 and find out whether the problem is recorded. A warning Fault code - a four-digit number that appears continually until the DTC does not wiped off the diagnostic tool. 5. In the list of DTCs troubleshoot element and restore its performance. 6. After erasing fault codes from the memory control unit for ABS, select inspection post ?��4.