Fail-Safe Function

When a malfunction is detected in system, solenoid valve operation is turned off by fail-safe relay. Under these conditions, the ABS system operates as a conventional brake system. The fail-safe function turns on when ABS warning light is turned on. ABS control unit has 4 fail-safe modes:

• Fail-Safe Mode "A": If ABS control unit detects a malfunction during an emergency stop, it will turn off malfunctioning component, and continue to modulate rest of ABS system until vehicle comes to a stop. At that time, entire system will be turned off until problem goes away. ABS indicator light is illuminated when a problem is detected.
• Fail-Safe Mode "B": ABS control unit will turn system off if ignition voltage drops too low, and will turn system on again when ignition voltage returns to normal. ABS indicator light is illuminated when a problem is detected and is turned off when problem goes away.
• Fail-Safe Mode "L": ABS control unit stores DTC in back-up memory when it detects a problem. If a problem is detected when ignition is turned on, ABS control unit will turn system off. If problem goes away, ABS control unit will turn system on again. ABS indicator light is illuminated when a problem is detected.
• Fail-Safe Mode "S": ABS control unit turns system off when ABS control unit detects a problem. ABS indicator light is illuminated when a problem is detected.