Fail-Safe Chart

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: FAIL-SAFE CHART





1. FAIL-SAFE FUNCTION

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

(b) When trouble occurs in the brake control system, the skid control ECU turns the warning light on, and prohibits ABS, BA, and VSC operations.





HINT
A malfunction in either the ABS or BA system will result in an identical operation, with the ABS, BA, TRAC and VSC system control disabled.





HINT
As for the TRAC and VSC systems, different systems prohibit different controls depending on the malfunctioning part.

(c) The skid control ECU prevents operation of a malfunctioning hydraulic system and continues brake control with a backup hydraulic system.

HINT
* If control of the electronically controlled brake system is prohibited for any of the wheels, that wheel loses brake accumulator function or braking ability.
* If one of the wheels loses brake accumulator function, the feeling when depressing the brake pedal changes as the stroke simulator (pedal reactive force generating solenoid) operation will be prohibited.
* If control of the electronically controlled brake system is prohibited for all wheels, the 2 front wheels will lose brake accumulator function.
(d) If the brake control is stopped under such conditions as when trouble 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.

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

(f) If the regenerative brake alone does not operate under such conditions as a communication error with the hybrid vehicle control ECU, control is switched so that all braking force is generated with hydraulic braking pressure.