ELECTRONICALLY CONTROLLED BRAKE SYSTEM FAIL-SAFE CHART


  1. FAIL-SAFE FUNCTION OF CONTROL SYSTEM


    1. If a malfunction occurs in the skid control ECU, sensor signal, or actuator, the remaining functioning components will maintain brake control.

    2. If a malfunction occurs in the brake control system, the skid control ECU turns the warning light on, and prohibits ABS, BA and VSC operations.

      Item Operation
      Malfunction in the ABS system ABS, BA, TRC and VSC control prohibited
      Malfunction in the BA system ABS, BA, TRC and VSC control prohibited
      Malfunction in the EBD system ABS, EBD, BA, TRC and VSC control prohibited
      Malfunction in the TRC system ABS, BA, TRC and VSC control prohibited
      Malfunction in the VSC system ABS, BA, TRC and VSC control prohibited

    3. A power back-up unit is built in as an additional power source to supply stable power to the system.

  2. FAIL-SAFE FUNCTION OF HYDRAULIC SYSTEM


    1. The skid control ECU 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 will lose brake power assist function

    2. If the brake control is stopped under such conditions as when a malfunction occurs with a hydraulic pressure source, the pressure generated in the master cylinder by the driver is applied to the front wheel cylinders to ensure braking force.

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

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