Hyundai Elantra AD Quiz
Brake System

Description and Operation

In this manual: Brake System
General Information — 9Engine Mechanical System — 84Engine Electrical System — 60Emission Control System — 24Engine Control System/Fuel System — 90Automatic Transmission — 92Drive Shaft and Axle — 20Suspension System — 31Steering — 20Restraints — 50Brake System — 63Body (Interior and Exterior) — 214Body Electrical System — 221Heating, Ventilation, and Air Conditioning — 71
6steps
~36min
2/5difficulty
Done 0 of 6

Description

This specification refers to the HCU (Hydraulic Control Unit) and the ECU (Electronic Control Unit) of the HECU (Hydraulic and Electronic Control Unit). This specification is intended for the wiring design and installation of the ABS ECU. This unit has the following functions.
  • Input of the signal from the wheel speed sensors attached to each wheel.
  • Brake force control.
  • Fail-safe function.
  • Self-diagnosis function.
  • Interface with external diagnostic tester.
Installation location: Engine compartment
  • The length of the brake pipe from the master cylinder port to the HECU inlet port must be max. 1 m.
  • The position must not be close to the engine block and not lower than the wheel.
The ECU operation is activated by turning on the operating voltage (IGN). After completion of the initialization phase, the ECU shall be ready for operation. In the operating state, the ECU shall be ready within the specified limits (voltage and temperature) to process the signals provided by the various sensors and switches according to the control algorithm defined by the software, and to control the hydraulic and electrical actuators. Wheel Sensor Signal Processing: The ECU shall receive the wheel rotation speed signal from the four active wheel sensors. The wheel signals are converted into a voltage signal by the signal conditioning circuit after receiving the current signal from the active wheel sensors, and are supplied as input data to the MCU. Solenoid Valve Control: When one side of the valve coil is connected to positive voltage, supplied through the valve relay, and the other side is connected to ground through the semiconductor circuit, the solenoid valve is energized. The electrical function of the coils is always monitored by a valve test pulse under normal operating conditions. Voltage Limits
  • Overvoltage: When an overvoltage is detected (above 16.8 V), the ECU turns off the valve relay and disables the system. When the voltage returns to the operating range, the system returns to normal after the initialization phase.
  • Undervoltage: When an undervoltage is detected (below 9.3 V), ABS control is inhibited and the warning lamp is turned on. When the voltage returns to the operating range, the warning lamp turns off and the ECU returns to normal operation.
Pump Motor Check: The ECU performs a check of the pump motor at 30 km/h speed once after the ignition is switched on. Diagnostic Interface: Faults detected by the ECU are coded in the ECU, stored in EEPROM, and read by diagnostic equipment when the ignition switch is on. The diagnostic interface can also be used to test the ECU during ECU production and to actuate the HCU (air-bleed line or roll and brake test line). Warning Lamp Module

[Supervision]

[General]

  1. ABS Warning Lamp: The active ABS warning lamp indicates the self-check and fault status of the ABS. The ABS warning lamp shall illuminate:
    A. During the initialization phase after IGN ON (continuously for 3 seconds).
    B. In case of ABS operation failure during braking.
    C. In diagnostic mode.
    D. When the ECU connector is disconnected from the ECU.
  2. EBD/Parking Brake Warning Lamp: The active EBD warning lamp indicates the self-check and fault status of the EBD. However, if the parking brake switch is on, the EBD warning lamp is always on regardless of the EBD status. The EBD warning lamp shall illuminate:
    A. During the initialization phase after IGN ON (continuously for 3 seconds).
    B. When the parking brake switch is on or the brake fluid level is low.
    C. When the EBD function has failed.
    D. In diagnostic mode.
    E. When the ECU connector is disconnected from the ECU.

ABS Control

  1. Normal Braking without ABS
    Inlet Valve (IV) Outlet Valve (OV) Return Pump
    Operation Open Close OFF

    • IV: Inlet Valve
    • OV: Outlet Valve
    • RL: Rear Left Wheel
    • FR: Front Right Wheel
    • FL: Front Left Wheel
    • RR: Rear Right Wheel
    • RP: Return Pump
  2. Decrease Mode
    Inlet Valve (IV) Outlet Valve (OV) Return Pump
    Operation Close Open ON (engine speed control)

    • IV: Inlet Valve
    • OV: Outlet Valve
    • RL: Rear Left Wheel
    • FR: Front Right Wheel
    • FL: Front Left Wheel
    • RR: Rear Right Wheel
    • RP: Return Pump
  3. Hold Mode
    Inlet Valve (IV) Outlet Valve (OV) Return Pump
    Operation Close Close ON (engine speed control)

    • IV: Inlet Valve
    • OV: Outlet Valve
    • RL: Rear Left Wheel
    • FR: Front Right Wheel
    • FL: Front Left Wheel
    • RR: Rear Right Wheel
    • RP: Return Pump
  4. Increase Mode
    Inlet Valve (IV) Outlet Valve (OV) Return Pump
    Operation Open Close ON (engine speed control)

    • IV: Inlet Valve
    • OV: Outlet Valve
    • RL: Rear Left Wheel
    • FR: Front Right Wheel
    • FL: Front Left Wheel
    • RR: Rear Right Wheel
    • RP: Return Pump

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