ELECTRONICALLY CONTROLLED BRAKE SYSTEM FAIL-SAFE CHART


  1. FAIL-SAFE FUNCTION OF CONTROL SYSTEM


    1. When a malfunction is detected in the brake control system, the skid control ECU assembly turns the ABS warning, brake warning / red (malfunction), brake warning / yellow (minor malfunction) and slip indicator lights on, flashes the brake hold operated indicator light*, as well as prohibits ABS, BA, TRC, VSC, brake hold and secondary collision brake operation.


      • *: The brake hold switch is turned on under the following vehicle conditions.


        • Vehicle Conditions:


          1. The driver side door is closed.

          2. The driver side seat belt is fastened.

    2. If the skid control ECU assembly detects that a system related to the SFI system is malfunctioning, it will prohibit operations of the TRC and VSC systems in order to prevent further malfunctions and to protect the systems.

    3. Brake hold control prohibits brake hold operation in order to protect the system and prevent improper operation when the electronically controlled brake system, electric parking brake system or SFI system is malfunctioning.

      Item Operation
      Malfunction in the ABS.

      ABS, BA, TRC and VSC control prohibited.

      Brake hold control prohibited*
      Malfunction in the BA system.

      ABS, BA, TRC and VSC control prohibited.

      Brake hold control prohibited*
      Malfunction in the EBD system.

      ABS, EBD, BA, TRC and VSC control prohibited.

      Brake hold control prohibited*
      Malfunction in the TRC system.

      ABS, BA, TRC and VSC control prohibited.

      Brake hold control prohibited*
      Malfunction in the VSC system.

      ABS, BA, TRC and VSC control prohibited.

      Brake hold control prohibited*

      • *: Only during brake hold control

    4. A power back-up unit is provided as an additional power source to supply stable power to the system.

  2. FAIL-SAFE FUNCTION OF HYDRAULIC SYSTEM


    1. The skid control ECU assembly prevents operation of a malfunctioning hydraulic system and continues brake control with a backup hydraulic system.

      Item Operation
      Control of the electronically controlled brake system is prohibited for any of the wheels. The wheel loses the brake power assist function or braking ability.
      One of the wheels loses brake power assist function.

      • Feeling when depressing the brake pedal changes.

      • Brake stroke simulator (pedal reactive force generating solenoid) operation will be prohibited.
      Control of the electronically controlled brake system is prohibited for all wheels. The front wheels lose brake power assist function.

    2. If brake control is stopped due to a malfunction in the hydraulic pressure source, the pressure generated in the master cylinder by the driver is applied to the wheel cylinders to ensure braking force.

    3. If the regenerative brake alone does not operate under such conditions as a communication error with the ECM control is switched so that all braking force is generated with hydraulic braking pressure.

      Item Operation
      Skid control ECU assembly malfunction. Normally operating components control brake and generated braking force.
      Hydraulic pressure controlling components malfunction. Normally operating components control brake and generated braking force.
      Power supply components (Hydraulic pressure source) malfunction. Braking force solely generated by the driver.