Fail-Safe Chart

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

FAIL-SAFE CHART





1. FAIL-SAFE FUNCTION
(a) If a malfunction occurs in the skid control ECU, sensor signal, or actuator, rest normally operating parts will maintain brake control.
(b) When trouble occurs in the brake control system, the skid control ECU turns the warning light on, displays a DTC corresponding to the malfunctioning systems on the multi information display, and prohibits ABS, BA, and VSC operations.

ABS, EBD and BA system:





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

TRAC and VSC system:





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

(c) The skid control ECU prevents operation of a malfunctioning hydraulic pressure system and continues brake control with the normal hydraulic pressure system.
HINT:
- If control of the Electronically Controlled Brake for any of the 4 wheels is prohibited, that wheel loses brake booster function or braking ability.
- If one of the 4 wheels loses brake booster 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 for all wheels is prohibited, the 2 front wheels will lose brake booster 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 wheel cylinder 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 HV control ECU, control is switched so that all braking force is generated with the hydraulic pressure brake.